Cultural Methods

Cultural pest control methods involve the use of various methodologies or techniques aimed at providing an unfavorable condition for the pests. It involves simple modifications of a pest’s environment or habitat and the manipulation of the agroecosystem in order to make the cropping system less friendly to the establishment and proliferation of pest populations. The practices lead to reduced pest establishment, reproduction, dispersal, and survival. The practices include; use of resistant varieties, crop rotation, crop refuse destruction, variation in time of planting or harvesting, pruning or thinning and proper spacing, crop sanitation and Water management planting of trap crops

 

Prevention

  1. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants

Control of perennial weeds

  1. Ground covering legume plants and mulches can play a very important role in both improving the soil fertility and combat perennial weeds. Clover and other leafy and strongly growing legumes planted in sedge infested land will both overpower the sedges and enrich the soil. In the case of watergrass or nutsedges, harrowing only makes the problem worse, as the root nuts will be separated from the stems and given the opportunity to send out many new shoots.
  2. Solarisation. Covering a sedge infested piece of land with black polythene after wetting it, and leaving it exposed for some days to hot sunshine, will completely eliminate any of the sedge species. However plastic is expensive, so if it cannot be afforded try the first option: ground cover with legumes. 
  3. Mulching. C. rotundus has been successfully controlled with heavy mulching. Initially the weeds grow prolifically, but after a wet period they are easy to remove by careful hand pulling making sure the “nut” does not stay in the soil. This does not work on hard unmulched soils.
  4. Hand digging. Very careful hand digging with a knife ensuring all the little underground bulbs are removed can give a small reduction in Oxalis populations (annual or perennial), but is very time consuming and bound to leave a few bulbs here and there which will waste no time in germinating.

 

Prevention

  1. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants

Control of annual weeds

  1. Digging or pulling the weeds and removing them from the field (in small gardens). This removes from the field all the nutrients collected by the weeds.
  2. Shallow cultivation at an early stage and leaving the weeds to dry on top of the soil either by hand or by animal or tractor mounted equipment. Tools include row cultivators, small grain seed spring harrows and hard brushes for row treatment. The first 2 methods as well as no 5 and 6 are developed in the cool temperate climates and generally aim to keep the soil in between crop plants bare. Under the African sun, bare soil is also unprotected soil. Unprotected soil is prone to erosion, crusting after heavy rains and general soil degradation. There will also be a flush of germination of weeds after every rainfall as nature strives to repair the damage, and repeated energy consuming weeding operations will need to be carried out.
  3. Slashing weeds at ground level when 10-15 cm tall and definitely before flowering, then leaving them on the ground as mulch, reduces the weeding work substantially. It is much lighter work to slash than to dig w

  4. ith a hoe (jembe) and intervals between slashing can be longer than between traditional weeding/digging. This method can also be using either hand slashing or animal/tractor drawn equipment such as mowers or the knife rollers developed by Conservation Agriculture studies in East Africa.
  5. Mulch: using plant material to cover the ground to avoid weed growth

 

Planting of ground cover plants

 especially legumes to crowd out further “weed” germination. This not only provides ground cover but also enriches the soil, and will eliminate further weeding operations. The legumes will often continue growing after the main crop is harvested, providing soil protection until the next crop is planted. They can also become useful for feeding livestock or for incorporating into the soil as green manure

Prevention

  1. Use Fungalsol and Calciumax 
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Use clean seed: Make sure that seeds/tubers for sowing and planting are certified and not taken from plants that were previously infected by the early blight. If possible, use potato and tomato varieties that are resistant to the disease. 
  4. Hot water treatment of seeds, where own seeds are used, could help reduce the incidence of seed-borne infection by early blight. It will also take care of other seed-borne problems caused by pathogens such as Phoma spp., Septoria spp. and bacterial pathogens.
    1. Specified temperatures and recommended time for treatment should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local extension office. 
    2. To make sure that the seed is not damaged it is advisable to test the germination of 100 heat-treated and 100 untreated seeds (more information on hot water treatment: https://www.infonet-biovision.org/PlantHealth/Hot-water-treatment).
  5. Use tolerant or resistant varieties: Use plant varieties that are tolerant or resistant to early blight. Examples of tolerant / resistant tomato varieties in Kenya: ‘Floradade’, ‘Hytec 36’, ‘Julius F1’, ‘Rio Grande’, ‘Rossol’, ‘Summerset F1’, ‘Zeal F1’ and ‘Zest F1’. 
  6. Destroy crop debris after harvest: Plough under all the crop residues after harvest to physically remove the inoculum (infection) source from the topsoil. Remove also weeds as they may serve as alternate hosts. Burn the infected material and plant debris. 
  7. Avoid injury to potato tubers during harvesting and handling: Harvest potato tubers when the soil is not wet and when the vines are dry.
  8. Practise proper plant spacing and staking: Prevent tomato plants from soil contact and prune and stake indeterminate varieties to promote good air circulation. 
  9. Water management: If possible avoid over-head irrigation. Otherwise, irrigate early in the morning so that the canopy would dry in the evening. In case of Irish potatoes, furrow irrigation should not be used especially after tuber formation.
  10. Soil management: Use plenty of compost or well decomposed animal manures. Maintain soil fertility at optimal levels. Nitrogen and phosphorus deficiency can increase susceptibility to early blight. Also excess nitrogen could induce early blight infection.

Monitoring: 

  1. Scout for brown circular leaf spots on the upper part of the leaves starting from the older leaves to the younger ones.
  2. Continue inspecting weekly, especially on the underside of the leaves.
  3. Check for brown to black circular rings on the fruits and premature fruit fall.
  4. Consider direct control when prolonged leaf wetness (85% per day) due to dew, rainfall and irrigation.
  5. Remove the leaves of the affected plants and bury them (1m deep) or burn.

Crop rotation: 

Fields should not be planted with tomato, Irish potato, or eggplant for at least 2 cropping seasons, since they are hosts to early blight. Also avoid planting new plots of these vegetables alongside old ones. Rotations with small grains, maize or legumes are preferable. 

Prevention

  1. Use Fungalsol to prevent and control
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Well drained soil is important
  4. Use resistant or tolerant varieties if they are available
  5. Avoid late-season applications of nitrogen fertilizer to limit the production of succulent tissue, which is more susceptible to infection.
  6. Avoid overhead watering to help reduce the relative humidity.
  7. Remove and destroy all infected plant parts (leaves, etc.). For infected vegetables and other annuals, remove after harvest as much as possible of the plant and its debris. This decreases the ability of the fungus to survive to next season. Do not compost infected plant debris. Temperatures in the compost often are not hot enough to kill the fungus.
  8. Encourage the entry of light and circulation of air:
    • Remove weeds and old leaves
    • Avoid high planting densities by planting at the recommended spacing 
    • Selectively prune overcrowded plant material 
  9. Do not plant downwind of old plantings of cucurbits since wind can spread powdery mildew
  10. Avoid excess nitrogen at the end of the season since it favours the fungus

Monitoring:

 Monitor every week for symptoms, starting from the vegetative stage and continuing until the fruit development.

  1. The first symptoms are angular yellow spots on the upper leaf surface
  2. the internal parts of these spots become brown with yellow margins Older plants are affected first. Symptoms usually appear on the lower, shaded, mature leaves (7-8 weeks old)
  3. Symptoms are often most severe on the underside of the leaves, fine, grayish fungal growth
  4. Consider taking action as soon as one plant is affected

Prevention

  1. Use Fungalsol to prevent and control
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Use resistant or tolerant varieties if they are available
  4. Avoid late-season applications of nitrogen fertilizer to limit the production of succulent tissue, which is more susceptible to infection.
  5. Avoid overhead watering to help reduce the relative humidity.
  6. Remove and destroy all infected plant parts (leaves, etc.). For infected vegetables and other annuals, remove after harvest as much as possible of the plant and its debris. This decreases the ability of the fungus to survive to next season. Do not compost infected plant debris. Temperatures in the compost often are not hot enough to kill the fungus.
  7. Encourage the entry of light and circulation of air:
    1. Remove weeds and old leaves
    2. Avoid high planting densities by planting at the recommended spacing e.g. 60 x 90 cm for cucumber
    3. Selectively prune overcrowded plant material 
  8. Do not plant downwind of old plantings of cucurbits since wind can spread powdery mildew
  9. Avoid excess nitrogen at the end of the season since it favours the fungus

Monitoring: 

Crops than can be affected include cucurbits such as pumpkin, melon, squash, gourd, and other crops such as tomato, snow peas and pepper.

  1. Monitor every week for symptoms, starting from the vegetative stage and continuing until the fruit development.
  2. The first symptoms are small and chlorotic (yellow/pale green) spots on leaves, stems and petioles
  3. These spots spread and produce a white dusty appearance on the surface of the affected areas
  4. Older plants are affected first. Symptoms usually appear on the lower, shaded, mature leaves (7-8 weeks old)
  5. Symptoms are often most severe on the underside of the leaves
  6. Fruit may appear sunburnt and pale, with speckling and small, raised areas. Ripening may be premature or incomplete.
  7. In case of severe infection, premature leaf senescence and death of the plant may be observed
  8. Consider taking action as soon as one plant is affected

Prevention

  1. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants. Termites more often attack sickly or water stressed plants than healthy plants.
  2. Do not locate seedbeds where vegetables have been grown previously. After preparation of the seedbed, burn the topsoil using dry leaves or other waste plant material.
  3. Maintain high levels of organic matter (manure and compost) in the soil.
  4. Solarise seedbeds if possible.
  5. Use biofumigation where possible. 
  6. Fields should be ploughed deep and the followed by a dry fallow.
  7. Uproot entire plants from the field after harvest and destroy crop debris.
  8. Use clean irrigation water (water which is unlikely to have run through nematode infested fields)
  9. Use M~forte soil bio~stimulant to Control Nematodes and other pathogens

Crop rotation: 

Rotate with onions, baby corn, sweet corn, maize, millet, sorghum, sesame, cassava or Sudan grass as these crops are less susceptible

A rotation system called “STRong” is recommended for management of root-knot nematodes. The system was developed by, African Farmers’ Organic Research and Training (AfFOResT), an NGO in Zimbabwe. 

It involves planting in rotation of a susceptible crop (e.g. tomatoes), followed by a tolerant crop (e.g. cabbage) and then a resistant crop (e.g. onions) before a return to a susceptible crop (e.g. tomatoes). Crop susceptibility of various commonly crops is given in the following Table. 

SusceptibleTolerantResistant
Bambara nutBrassicasCassava
BeansChilli pepperGarlic
BeetrootRadishLeek
CarrotSweet potatoMaize
CeleryTurnipMillet
Cowpea Rhodes grass
Cucumber Sesame
Eggplant Sorghum
Gourd Sudan grass
Irish potato Sweet corn
Lettuce  
Melon  
Okra  
Parsley  
Peas  
Pumpkin  
Squash  
Sweet pepper  
Swiss chard (spinach)  
Tomato  
(Source: Dobson et al. 2002)  

Mixed cropping: 

Different mustards (e.g. Brassica juncea var. integrifolia orBrassica juncea var. juncea) should be used as intercrop on infested fields. As soon as mustards are flowering they are mulched and incorporated into the soil. While incorporated plant parts are decomposing in a moist soil, nematicidal compounds of this decomposing process do kill nematodes. Two weeks after incorporating plant material into the soil a new crop can be planted or sown.

Trap crops: Usetrap crop such as marigold (Tagetes spp.) and Indian mustard. (A trap crop is a crop planted to attract a pest and is then destroyed together with the pest). Mixed cropping with marigold can also minimise root-knot nematode damage.

Monitoring:  

Regular monitoring is vital for timely action. 

  1. Before planting, sample for nematodes at the end of a growing season, when crop residues remain (when nematode populations are high):
    1. Collect soil and root samples from 10 to 20 locations in the field, at a depth of 15-25 cm, using a cylindrical sampling tube, trowel or shovel. Emphasize taking soil samples across rows rather than within rows
    2. Take one sample per 5-10 acres. Samples should be taken when soil is not extremely wet or dry
    3. Add a 1-2 pint sub-sample to a plastic bag. Keep well sealed and at ambient temperature and light levels. Send these to a lab
    4. If at least 5 root knot nematodes are found in 200 g soil then consider control options before planting, or planting a less susceptible crop (see below)

During growing season look out for: 

  1. Slow/stunted growth, yellowing of the leaves, wilting of plant despite adequate soil water content
  2. Fleshy galls on the roots that do not flick off easily on touching
  3. Numerous death of plants in the seed bed and seedlings do not survive transplanting
  4. Collapse of the individual infected plants
  5. Symptoms can look similar to that of nutrient deficiency (stunting, leaf discolouration). However, this does not result in root galls caused by nematodes
  6. Check for nematodes by digging up plants from several areas of the field and checking for galls. If 25-30% of the plants show symptoms then consider taking action.

References

  1. http://oisat.org/pests/nematodes/root_knot_nematode/root_knot_nematode.html
  2. https://www.infonet-biovision.org/PlantHealth/Pests/Root-knot-nematodes
  3. https://www.plantwise.org/KnowledgeBank/pmdg/20177801166

Prevention

  • ensure adequate growing conditions Ensure for the crop such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  • maintain natural surroundings (trees, shrubs) attracts natural enemies 
  • Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hoverflies.
  • Clip off shoots that contain caterpillars while the insects are young and feeding in groups. 
  • Spray Stopgel through out the life cycle of the pest.

Crop rotation: 

Rotate with non-brassicas such as onions, maize and beans for at least one season. 

Mixed cropping:

 Brassica should be intercropped with other crops. Onions, chillies and tomatoes can be intercropped with brassicas.

Trap Crops: Plant trap crops such as mustard and rape at the edges of the field to reduce DBM attack.

Monitoring: 

Regular scouting during seedling and shoot growth and during flowering and fruiting is very important (at least twice a week, as they can rapidly increase). Inspect the underside of terminal leaves for egg masses and groups of small caterpillars at least once a week. 

References

  1. https://www.infonet-biovision.org/PlantHealth/Pests/Diamondback-moth-DBM
  2. http://oisat.org/pests/insect_pests/caterpillars_grubs/diamondback_moth/preventive_control.html
  3. https://www.plantwise.org/KnowledgeBank/pmdg/20157800741
  4. KIOF – Kenya Institute of Organic Farming, Nairobi.

Prevention

  • ensure adequate growing conditions Ensure for the crop such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  • maintain natural surroundings (trees, shrubs) attracts natural enemies 
  • Weeds play an important role in harbouring whiteflies between crop plantings. They also often harbour whitefly-transmitted viruses. Therefore, weeds should be removed in advance of planting. Fields should also be kept weed free.
  • Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hoverflies.
  • Make sure that the soil is not drying out completely. Dusty surroundings enhances spider mite occurrence. Mites favour dry and hot conditions. Influencing the microclimate by reducing the planting distance is reported to suppress spider mite populations. However, this could also enhance fungal diseases, so care should be taken.
  • Remove and burn infested crop residues immediately after harvest
  • Use Stopgel organic foliar as a pesticide

Mixed cropping: 

Keep perennial hedges such as pigeon peas, they are said to encourage predatory mites, which predate on spider mites.

Crop rotation: 

Rotate crop with non-host plants such as maize, pulses or chive.

Nutrient Management: 

Avoid high levels of nitrogen in soil, as this causes plants to become succulent and attractive to spider mites.

Monitoring: 

Regular scouting during seedling and shoot growth and during flowering and fruiting is very important. Mites are tiny and difficult to detect. You’ll usually notice plant damage such as stippled or yellow leaves before you spot the mites themselves (Figure 6). Check the undersides of leaves for mites, their eggs, and webbing; 

References

  1. http://oisat.org/pests/insect_pests/mites/spider_mites/preventive_control.html
  2. https://www.infonet-biovision.org/PlantHealth/Pests/Spider-mites
  3. https://www.plantwise.org/KnowledgeBank/pmdg/20187800513

Prevention

Controlling fusarium once it has established is very difficult. The most important way of controlling fusarium is attempting to prevent its establishment and further spread.

  1. Use M~Forte soil biostumulant as a preventive measure
  2. Avoid fields with a long history of Fusarium wilt.
  3. Deeply plough the fields and leave them fallow for 2-3 months, where feasible
  4. Use certified, disease-free seeds
  5. Use resistant varieties, e.g. tomatoes: ‘Diego’, ‘Duke’, ‘Floridade’, ‘Fanny’, ‘Fortune Maker’, ‘Napoli’, ‘Radja’, ‘Roma VF’, ‘Roma VFN’ and ‘Tengeru 97’. Graft tomato plants on resistant root stocks where available.
  6. Raise soil pH by applying lime or farmyard manure where soil is acidic. Do not use chicken manure, which is very acidic.
  7. Control root-knot nematodes. To find out more on root-knot nematodes click here
  8. Keep fields weed-free
  9. Regularly irrigate the crop
  10. Hot water treatment of seeds, where own seeds are used, could help reduce the incidence of seed-borne infection by leaf spot. It will also take care of other seed-borne problems caused by pathogens such as Phoma spp., Septoria spp. and bacterial pathogens.
    1. Specified temperatures and recommended time for treatment should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local extension office.
    2. To make sure that the seed is not damaged it is advisable to test the germination of 100 heat-treated and 100 untreated seeds (more information on hot water treatment: https://www.infonet-biovision.org/PlantHealth/Hot-water-treatment).

 

Monitoring: 

Symptoms often appear later in the growing season and are first noticed on the lower (older) leaves

Look out for the symptoms for the different crops (see Symptoms)

 

  1. Ensure that symptoms are caused by fusarium wilt and not bacterial wilt which induces similar symptoms. Plants affected by bacterial wilt produce a milky exudate from stem pieces placed in water
  2. Hand pull infected plants and destroy by burning (if allowed in your area). Alternatively place in trash. Be sure to destroy/get rid of any plant residues so that they are not left to harbour and spread the disease. Do not compost.

Crop rotation: 

Because Fusarium persist several years in soil, a long crop rotation (4 to 6 years) is necessary.

  1. Avoid using any solanaceous crop (potato, tomato, pepper, eggplant) or other host plants in the rotation. Rotate with cereals and grasses wherever possible.

References

  1. http://oisat.org/pests/diseases/fungal/fusarium_wilt.html
  2. https://www.infonet-biovision.org/PlantHealth/Pests/Fusarium-wilt
  3. https://www.plantwise.org/KnowledgeBank/pmdg/20177801160

1 Prevention

  1. Apply stopgel on the leaves and fruits
  2. Ensure adequate growing conditions Ensure for the crop such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Maintain natural surroundings (trees, shrubs) attracts natural enemies 
  4. Use only thrips-free seedlings from certified nurseries
  5. Sow early just after the onset of the rains to avoid thrips incidence
  6. Control weeds in and around the fields or greenhouses to reduce thrips population
  7. Use UV-reflective mulches to disrupt host location by the thrips
  8. Mulch with dry grass or polythene to prevent thrips to pupate in the ground
  9. Plough and harrow the field after harvest to reduce thrips survival
  10. Keep old fields away from new ones (other vegetables, tobacco and commercial flower plants)
  11. Avoid planting tomatoes next to onions, garlic, or cereals, because high thrips numbers often build up on these crops
  12. Avoid using fields near greenhouses where ornamentals (cut flowers) are grown as these plants serve as hosts for the virus and thrips
  13. Balanced fertilization minimizes preference of thrips for a crop
  14. Carefully clean equipment with bleach after use in fields or greenhouses
  15. Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hoverflies.

2. Monitoring

  1. Monitor regularly for thrips or symptoms from seedlings until harvest by shaking leaves and flowers onto a white piece of paper
  2. Insect: 
  3. Adult thrips are small and thin insects less than 1 mm with 4 long, narrow fringed wings. Adults are pale yellow to light brown in colour
  4. Immature stages are yellowish in colour

 

3. Symptoms:

  1. Feeding by adults and immatures causes silverish spots, distorts plant growth and deforms flowers. They usually feed on the young lower leaf surface, buds, flowers and fruits
  2. Floral abortion occurs and affected fruits are of poor quality when flower buds are attacked
  3. Fruits will be marked with tiny dimples caused by adults laying eggs and light brownish flecks caused by feeding larvae
  4. Take action as soon as you notice one thrip adult on a flower or evidence of any larvae on fruit (look for dimples and flecking on fruit for evidence)
  5. Initiate control measures when 10% of the plants display symptoms of Tomato spotted wilt virus (see our green list for TSWV)
  6. Daily overhead irrigation (2-5 mm) at midday to reduce thrips. Leaves must dry quickly to avoid diseases
  7. Flood the field after harvest to destroy pupae in the soil

  1. During land preparation stumps, pieces of wood and roots of forest trees must be removed from the soil
  2. If Armillaria occurs in established tea, diseased trees must be thoroughly removed so that they do not become a source of infection for the neighbouring bushes.
  3. Use M~Forte to prevent

Prevention

  1. Good store hygiene is very important in limiting infestation.
    1. Clean store thoroughly between harvests.
    2. Store only clean produce. Carefully inspect the store before the newly harvested maize or cassava is placed inside and sort out infested cobs or roots for immediate use.
    3. Remove and burn infested residues before the new stock is stored. Immerse used sacks in boiling water to eliminate residual infestations.
    4. Eliminate residual infestation in the wooden structure of the store by removing timber or by fumigating the whole store under a gas-tight sheet.
  2. When maize is ready for harvest, do not leave it for too long in the field; the larger grain borer or other storage pests could attack it. Studies in Benin have shown that maize harvested 3 weeks after physiological maturity gave better economic returns when stored for 8 months than maize harvested 1 or 7 weeks after physiological maturity. 
  3. Make sure that the bags are stored on pallets at a sufficient distance from the ground, away from the walls and avoid touching the roof.
  4. Store the grain in a suitable container. The larger grain borer easily attacks grains stored in gunny bags or guards. Moreover, this pest also damages guards. The most suitable containers are those that can be sealed such as metallic containers, old oil drums or mudded cribs or baskets. They provided a very effective barrier to pest attack and can be used provided the stock is sufficiently dried so that ventilation is not required.
    1. Use of modern structures such as improved granaries and mini silos building them well isolated, ventilated and with the least possible windows and cracks
  5. Use brick stones to construct the granaries; wood and grass would encourage breeding and multiplication of the larger grain borer.
  6. Prefer iron sheet roof for the stores to avoid harbouring the pest. If using grass thatched, it should be a thick layer and cone shaped; the roofing should be replaced after a certain interval period to minimise leaking.
  7. Sell the maize within 3 months since the extent of larger grain borer infestation during the first 3 months of storage is generally low. 
  8. Dry maize grains in the sun to achieve 13% of moisture content
  9. Apply a thin layer of ash to cover the grain in store to protect them against weevil attacks
  10. Use Stopgel to kill the Weevils

Monitoring:  

  1. Inspect once a week the stored grains in bags and sacks for weevils or grain borer or damaged grains and redrying and reterating if infested
  2. Regularly inspect the floors and walls of the store for signs of weevils
  3. Sieve infested grains and dry again in the sun to kill the remaining eggs and adults

References

  1. Borgemeister, C., Holst, N. and Hodges, R. J. (2003). Biological Control and Other Pest Management Options for Larger Grain Borer (Prostephanus truncatus). In Biological Control in IPM Systems in Africa. Eds. P. Neuenschwander, C. Borgemeister and J. Langewald). ISBN: 0-85199-639-6.
  2. Stoll, G. (2003). Natural Crop Protection in the tropics. Margraf Publisher. www.naturalcropprotection
  3. KIOF, Kenya Institute of Organic Farming, Kenya
  4. https://www.infonet-biovision.org/PlantHealth/Pests/Larger-grain-borer-LGB 
  5. https://www.plantwise.org/KnowledgeBank/pmdg/20177801297

Prevention

  1. Use Fungalsol foliar as a preventative fungicide
  2. Also use M~forte to boost immunity 
  3. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  4. Use clean seed: Make sure that seeds/tubers for sowing and planting are certified and not taken from plants that were previously infected. 
  5. Hot water treatment of seeds, where own seeds are used, could help reduce the incidence of seed-borne infection by leaf spot. It will also take care of other seed-borne problems caused by pathogens such as Phoma spp., Septoria spp. and bacterial pathogens.
    1. Specified temperatures and recommended time for treatment should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local extension office. 
    2. To make sure that the seed is not damaged it is advisable to test the germination of 100 heat-treated and 100 untreated seeds (more information on hot water treatment: https://www.infonet-biovision.org/PlantHealth/Hot-water-treatment).
  6. Keep weeds under control at all times. Keep the surroundings of your farm free of weeds, unless they are maintained and intended as habitat for natural enemies.
  7. Make yourself ‘clean’. Always bear in mind that you might be the carrier of the diseases while you move from one plant to another 
  8. Pull out plants that are heavily infected. 
  9. Prune the plant parts of fruit trees that show severe symptoms of disease infection. 
  10. Properly dispose of all the infected plants. 
  11. Pick rotten fruits and collect those that have dropped and bury in a pit. 
  12. Plough-under the crop residues and organic mulches. This improves soil condition and helps to disrupt the disease lifecycle.
  13. Maintain cleanliness on the irrigation canals. 
  14. Clean your farm tools. Wash ploughs, harrows, shovels, trowels and pruning gears after use. Lightly oil pruning gears.

Monitoring: 

Look out for:

  1. Brick-red to-dark brown sunken elongate lesions on the stems, leaf petioles and veins on the undersurface of the leaves
  2. Brick-red to dark-brown sunken and circular lesions on the pods
  3. Discoloured seeds which may have lesions
  4. Gelatinous masses of pinkish spores developing from infected areas during the moist weather
  5. Avoid unnecessary movement in the infected areas to minimise spread of the disease
  6. Disinfect farm implements after working from one field before proceeding to the other

Crop rotation: 

  1. Take notes of plants that are susceptible to anthracnose disease and rotate these with those that are resistant
  2. No further specific advise on crop rotation

Prevention

  1. Use Fungalsol to prevent and control
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Use clean seed: Make sure that seeds/tubers for sowing and planting are certified and not taken from plants that were previously infected by the late blight. If possible, use potato and tomato varieties that are resistant to the disease. 
  4. Hot water treatment of seeds, where own seeds are used, could help reduce the incidence of seed-borne infection by late blight. It will also take care of other seed-borne problems caused by pathogens such as Phoma spp., Septoria spp. and bacterial pathogens.
    1. Specified temperatures and recommended time for treatment should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local extension office. 
    2. To make sure that the seed is not damaged it is advisable to test the germination of 100 heat-treated and 100 untreated seeds (more information on hot water treatment: https://www.infonet-biovision.org/PlantHealth/Hot-water-treatment).
  5. Use tolerant or resistant varieties: Use plant varieties that are tolerant or resistant to late blight. Examples of tolerant / resistant potato varieties in Kenya: ‘Asante’, ‘Tigoni’.
  6. In Tanzania, the following commercial tomato varieties have been claimed to have some be resistance to late blight: “Meru”, “Tengeru 97” and “Shengena”.
  7. Destroy crop debris after harvest: Plough under all the crop residues after harvest to physically remove the inoculum (infection) source from the topsoil. Remove also weeds as they may serve as alternate hosts. Burn the infected material and plant debris. 
  8. Avoid injury to potato tubers during harvesting and handling: Harvest potato tubers when the soil is not wet and when the vines are dry.
  9. Practise proper plant spacing and staking: Prevent tomato plants from soil contact and prune and stake indeterminate varieties to promote good air circulation. 
  10. Water management: If possible avoid over-head irrigation. Otherwise, irrigate early in the morning so that the canopy would dry in the evening. In case of Irish potatoes, furrow irrigation should not be used especially after tuber formation.
  11. Soil management: Use plenty of compost or well decomposed animal manures. Maintain soil fertility at optimal levels. Nitrogen and phosphorus deficiency can increase susceptibility to late blight. Also excess nitrogen could induce early blight infection.

Monitoring: 

  1. Scout for brown circular leaf spots on the upper part of the leaves starting from the older leaves to the younger ones.
  2. Continue inspecting weekly, especially on the underside of the leaves.
  3. Check for brown to black circular rings on the fruits and premature fruit fall.
  4. Consider direct control when prolonged leaf wetness (85% per day) due to dew, rainfall and irrigation.
  5. Remove the leaves of the affected plants and bury them (1m deep) or burn.

Crop rotation: 

  1. Tomatoes: Rotate tomatoes with crops like beans, maize, cowpeas, onions, sweet potatoes and carrots.
  2. Do not plant potato near tomato or other solanaceous crops when disease has occurred, as the disease can easily spread from one to the other. Rotation will only be effective if it is done in cooperation with neighbouring farmers since the fungal spores of late blight can wind travel quite large distances.

Prevention 

  • Spray Stopgel on the foliage
  • ensure adequate growing conditions Ensure for the crop such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants 
  • maintain natural surroundings (trees, shrubs) attracts natural enemies 
  • Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hover flies.

Mixed cropping:

 Common mixed cropping includes use of companion planting and intercropping.

  • Anise, chives, garlic, onions, radish, parsley and Mexican Marigold are reported as good companion crops (Elwell and Maas, 1995; KIOF) as they repel aphids. Alternating rows is advisable. The Kenya Institute of Organic Farming (KIOF) recommends leaving a few plants of Mexican marigold between the crops.
  • Intercropping beans with maize. It has been shown that infestations of black bean aphid in common beans were greatly reduced when intercropped with older and taller maize plants in a study in Kenya (Ogenga-Latigo et al., 1993).
  • Numbers of the aphid in potatoes that were intercropped with onions (Allium cepa or Allium sativum). To achieve this reduction, the onions had to be planted within 0.75 m of potato plants (Potts MJ, Gunadi N, 1991).

Trap crops:

some crops are particularly attractive to pests and can be used to trap them and protect the main crop. It is important too destroy them and bury them before aphids can move over to the main crops. 

  • dill, nasturtiums, and timothy grass near the main crop are reported to avoid aphid infestations in the main crop.

Nutrient Management: 

Avoid high levels of nitrogen in soil, as this causes plants to become succulent and attractive to aphids.

Monitoring: 

Regular scouting during seedling and shoot growth and during flowering and fruiting is very important. 

  • Monitor at least 3 times a week for aphids early in the morning/late in day during dry periods.

To monitor aphid populations, examine the undersides of the leaves and the bud areas for groups or colonies of aphids. Presence of ants may indicate presence of aphids. Early detection of aphids is important as they can multiply rapidly. Yellow traps are useful for monitoring the arrival of winged aphids to the crop.

  • Look for yellowing leaves, stunted growth and honeydew on infested crops. Sooty mould may grown on the honeydew.
  • Look for curled, wrinkled or cupped leaves and mosaic patterns on the leaves (alternating dark and light patches) – these are symptoms of viruses that can be transmitted by the aphid

Damage thresholds depends on many factors (crop stages, crop age, economic and climatic conditions) but generally start control measures when there is 10-20% infestation (i.e. 1-2 infested plants/10-20 plants in plots).

Prevention

  1. Drench M~Forte in the soil near the plant roots and leaves to boost plant Resistance and also Spray fungalsol on the leaves to prevent Fungi 
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Use clean seed: Make sure that seeds/tubers for sowing and planting are certified and not taken from plants that were previously infected. 
  4. Hot water treatment of seeds, where own seeds are used, could help reduce the incidence of seed-borne infection by leaf spot. It will also take care of other seed-borne problems caused by pathogens such as Phoma spp., Septoria spp. and bacterial pathogens.
    1. Specified temperatures and recommended time for treatment should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local extension office. 
    2. To make sure that the seed is not damaged it is advisable to test the germination of 100 heat-treated and 100 untreated seeds (more information on hot water treatment: https://www.infonet-biovision.org/PlantHealth/Hot-water-treatment).
  5. Destroy crop debris after harvest: Plough under all the crop residues after harvest to physically remove the inoculum (infection) source from the topsoil. Remove also weeds as they may serve as alternate hosts. Burn the infected material and plant debris. 
  6. Practise proper plant spacing and staking: 
  7. Water management: If possible avoid over-head irrigation. Otherwise, irrigate early in the morning so that the canopy would dry in the evening. 
  8. Soil management: Use plenty of compost or well decomposed animal manures. Maintain soil fertility at optimal levels. 

Monitoring

Regularly check crop, especially when full canopy has developed, as the resulting high relative humidity in the canopy encourages disease development

Favourable conditions for disease development include high humidity and temperatures between 22 and 30°C. 

  1. Scout for brown circular leaf spots on the mainly on the lower part of leaves
  2. Spots vary between crops

Crop rotation

No advise on crop rotation

Prevention

  1. Also use fungalsol to prevent fungal diseases
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Prune properly after harvest to maintain open penetration and improve aeration
  4. Remove old stems and thin out branches as the old stems are more susceptible than young ones
  5. Change the crop cycle after every 7 years
  6. Do a pre-rain preventive spray before the short and long rain seasons. (see yellow direct control)
  7. Pluck off diseased berries, collect in a container and destroy by burning or burying
  8. Cut back the affected plants and graft gradually using resistant varieties like Ruiru 11 or Batian

Monitoring: 

  1. During wet, cold and humid conditions inspect for: – Brown black sunken spots on berries – Lesions on young berry stalk that shed off – Visible pink spore masses on lesions – Black berries
  2. Apply direct control immediately after noting signs of disease
  3. Spray Ruesil organic foliar.

References

  1. https://www.plantwise.org/KnowledgeBank/pmdg/20137804326

Prevention

  1. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  2. Use resistant or tolerant varieties if they are available
  3. Avoid overhead watering to help reduce the relative humidity.
  4. Remove and destroy all infected plant parts (leaves, etc.). For infected vegetables and other annuals, remove after harvest as much as possible of the plant and its debris. This decreases the ability of the fungus to survive to next season. Do not compost infected plant debris. Temperatures in the compost often are not hot enough to kill the fungus.
  5. Encourage the entry of light and circulation of air: 
    1. Remove weeds and old leaves
    2. Avoid high planting densities by planting at the recommended spacing 
    3. Selectively prune overcrowded plant material 
  6. Do not plant downwind of old plantings of other host plants since wind can spread 
  7. Practise crop rotation with non-cereal crops at least every 2-3 years (e.g. beans, chickpea)
  8. Plant maize in rows in the direction of prevailing winds for maximum air circulation

 

Monitoring:

Monitor the plant every week, especially when there are favourable environmental conditions (Mild (16-25 °C) and humid conditions (>95%) favour rust development).

  1. The first symptoms are small and pale-yellow spots on the leaves
  2. Spots gradually increase in size and become tan or brown in colour.
  3. The spots turn into pustules, which eventually coalesce to form larger pustules that break open, releasing masses of spores.
  4. Consider taking action as soon as one plant is affected
  5. Use Stopgel foliar as a preventative

References

  1. http://oisat.org/pests/diseases/fungal/rust_disease.html
  2. https://www.plantwise.org/KnowledgeBank/pmdg/20157800281

Prevention

Controlling botrytis once it has established is very difficult. The most important way of controlling it is attempting to prevent its establishment and further spread.

Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants

  • Use Stopgel to control vector pest and M~Forte To boot plant resistance
  • Use clean seed: Make sure that seeds/tubers for sowing and planting are certified and not taken from plants that were previously infected. 
  • Hot water treatment of seeds, where own seeds are used, could help reduce the incidence of seed-borne infection by leaf spot. It will also take care of other seed-borne problems caused by pathogens such as Phoma spp., Septoria spp. and bacterial pathogens. 
    • Specified temperatures and recommended time for treatment should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local extension office. 
    • To make sure that the seed is not damaged it is advisable to test the germination of 100 heat-treated and 100 untreated seeds (more information on hot water treatment: https://www.infonet-biovision.org/PlantHealth/Hot-water-treatment).
  • Destroy crop debris after harvest: Plough under all the crop residues after harvest to physically remove the inoculum (infection) source from the topsoil. Remove also weeds as they may serve as alternate hosts. Burn the infected material and plant debris. 
  • Practise proper plant spacing and staking: 
  • Water management: If possible avoid over-head irrigation. Otherwise, irrigate early in the morning so that the canopy would dry in the evening. 
  • Soil management: Use plenty of compost or well decomposed animal manures. Maintain soil fertility at optimal levels. 
  • Harvest during dry conditions to prevent spreading the disease to other crops
  • Do not store any plants displaying symptoms as the disease can spread to other plants during storage
  • Store crop in a cool, dry place which is well aerated to suppress bacterial growth
  • Locate nurseries away from production fields and transplant to well drained soils
  • Control insect pests which can cause damage (e.g. thrips, leaf hoppers, cutworms), providing entry points for the bacteria. Practice tillage before planting to expose insect pupae to natural enemies to reduce populations
  • Fields should not be worked while plants are wet to avoid spreading the disease
  • Avoid injuries to plants when working to prevent bacteria from being able to easily enter the plant
  • Clean farming tools and machinery with 10% bleach or 70% alchohol before working in different areas of the field to prevent disease spread

Monitoring

  • Monitor the field looking for small to large water-soaked lesions on the leaves
  • Affected leaf tissues turn brown, becomes soft and mushy and has a foul smell. Leaves may yellow and wilt
  • Look for decaying leaves, stems and roots
  • Consider taking action as soon as the symptoms are seen
  • Rogue and destroy infected plants in nurseries and fields by deep burying (at least 1 m) or burning (if allowed in your area)
  • Destroy plant residues and volunteer crops by deep burying or burning

 

Crop rotation: 

  • Rotate with less susceptible crops such as maize, sorghum, snap beans and beets for 2-3 years after harvest

References

  1. https://www.plantwise.org/KnowledgeBank/pmdg/20167800921
  2. https://www.plantwise.org/KnowledgeBank/pmdg/20177801170

 

Prevention

  1. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants. Termites more often attack sickly or water stressed plants than healthy plants.
  2. Maintain natural surroundings (trees, shrubs) attracts natural enemies 
  3. Avoid unnecessary injury to the plants as this may facilitate entry of termites.
  4. Plough field to destroy termites’ nest, runways, and tunnels and to expose them to predators such as ants, birds, chicken, etc.
  5. Remove plant residues and other debris especially moist and decaying woods. However, ensure there is plenty of soil humus; avoid bare, dry disturbed, organic-deficient, residue-free soil (if there is no other food available termites will attack the crop) 
  6. Harvest at the right time, as termites often attack maize, sorghum and millet left in the field after maturity. The attacked stalks may fall down and the termites may attack the cobs and panicles.
  7. Locate their soil runways/tunnels and destroy the worker termites either by hand tilling or by flooding. This is not a long lasting solution since the termites would eventually re-infest the plants.
  8. Destroy termite mounds manually. However, this method is labour intensive since the building material of the mounds is very hard, and some mounds are large. To be effective the queen has to found and destroyed; the queen maybe hidden deep inside and is not easily found. After killing the queen, pour boiling water or burn dried grass straws (any plant debris) to kill the rest.
  9. Spray Stopgel on the termites

Crop rotation: 

Practice crop rotation to reduce the build-up of termites. Planting the same crop every cropping season makes it susceptible to termite attack. Crop rotation with non-host plants like beans. 

Mixed cropping: 

Grow crops in mixed cropping systems to lessen termite damage. Know and make a list of the annual crops that are attacked by termites. 

  1. Plant agroforestry trees such as Sesbania trees between the maize crop
  2. Plant repellent vertigrass, hot chilli peppers, or Mexican marigold in or around the field to repel termites.

Monitoring:  

Regular monitoring is vital for timely action. 

  1. Inspect plants for termite attack early in the season. Do this twice a week early in the morning or late in the afternoon as termites might have moved deeper into the soil during the day to shelter from high temperatures
  2. Look for whitish wingless, pale yellowed headed ant-like insects about 1-2 cm long.
  3. Look for 0.5 to 1 metre tall termite mounds in or around the field and lodging of the crop by observing the base of the plants for signs of chewing and soiling.
  4. Look for plant stems covered with closed soil runways or soil sheeting under which termites are found
  5. Threshold level is 5 to 10 plants are affected in 1 acre 

References

  1. Gold, C. S.; Wightman, J. A. and Pimbert, M. (1989). Mulching effects on termite scarification of drying groundnut pods. Int. Arachis Newsl. 6, 22-23.
  2. Schmutterer, H. (2002). Effect on Viruses and Organisms; Isoptera: Termites. In ‘The Neem Tree- Source of Unique Natural Products for Integrated Pest Management, Medicine, Industry and Other Purposes’. Second Edition. Edited by H. Schmutterer. pp. 320-321.
  3. https://www.plantwise.org/KnowledgeBank/pmdg/20177801145
  4. http://oisat.org/pests/insect_pests/termites_ants/termites/curative_control.html
  5. https://www.infonet-biovision.org/PlantHealth/Pests/Termites

Prevention

Control of armyworms is a large-scale venture and requires international collaboration. It usually involves early warning based on light traps or pheromone catches, or forecasts based on prevailing meteorological conditions. Accurate monitoring and prompt reporting of armyworm outbreaks is essential for forecasting and control.

  1. Use Stopgel foliar throughout the life cycle of the pest
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Cut grass weeds from bordering fields.
  4. Plough and harrow field thoroughly. Turning the soil exposes armyworm pupae to desiccation and natural enemies. 
  5. Maintain natural surroundings (trees, shrubs) attracts natural enemies 
  6. Some maize varieties are more susceptible to attack than others, e.g. Katumani, a dryland variety grown widely in Eastern Kenya. These varieties are most at risk where probabilities of armyworm infestation are high. 
  7. Avoid burning and overgrazing of grasslands, which are the natural habitat and food store of the caterpillars. Burning often causes outbreaks because as soon as temperatures rise, eggs are laid in large quantities on the fresh new grass. 

Crop rotation: 

Rotate with maize, legumes, cabbages, carrots and onions

Mixed cropping: 

Push and Pull methods. Napiergrass as bordering plants and Desmodimum intercropped with maize. 

Trap Crops: 

Napiergrass

Monitoring:  

Regular monitoring is vital for timely action. 

Armyworms feed at night and hide under debris during the day. Solitary forms are usually sparsely distributed and difficult to find. 

However, they can be monitored in late evening or early morning as they may still be actively feeding. Look in field margins, low areas where plants have lodged, beneath plant debris around the base of plants, and underneath the plant leaves. Examine 100 plants at random by examining 20 plants from 5 locations. 

  1. Look for creamy / grey egg masses covered in a felt-like layer of grey-pink scales on the underside of leaves 
  2. Look for caterpillars having a dark head with a distinct pale, upside-down Y-shape on the front and 4 dark spots on the second-to-last body segment

Hand-pick the caterpillars and feed these to chickens and ducks. 

A recommendation for monitoring armyworms is to examine 100 plants at random by examining 20 plants from five locations. At early whorl stage, take action if >20% of plants are damaged or infested with larvae. At late whorl stage, if small larvae can be found then consider taking control measures if >40% of whorls are damaged. At tassel and silk stage, do not spray anymore

Other physical methods: 

  1. Plough a deep ditch. Keep it filled with water. This method is helpful, when caterpillars are found to be moving towards your field from the adjacent fields.
  2. Another method is to dig a deep ditch with vertical sides to trap the caterpillars and prevent them from crawling out. Dig a hole, a diameter of a fence post, in every 10 meters within the ditch. Caterpillars are lured to congregate in the holes. Collect and properly dispose the trapped caterpillars
  3. Make pitfall traps – see image below
  4. Use light traps. They can provide useful information about the population of moths and therefore of caterpillars. Light traps help to predict if there is going to be an outbreak. However, light traps attract many other insects, including other moths. Therefore, it is very important to be able to recognise moths of the African armyworm. Use of light traps is primarily a tool in monitoring. In addition, a wooden tripod with a kerosene lantern is a ”light trap” locally improvised.

Prevention

  1. Apply Stopgel on leaves, eggs and larva
  2. ensure adequate growing conditions Ensure for the crop such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. maintain natural surroundings (trees, shrubs) attracts natural enemies 
  4. Clip off shoots that contain caterpillars while the insects are young and feeding in groups. At this stage, you’ll need to prune off only the infested shoot terminals to destroy a large group of caterpillars. Crush the caterpillars add them to your compost or feed them to your chicken if you have. 
  5. Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hoverflies.

Mixed cropping: 

Lavender, Sage repels many caterpillars

Trap Crops: 

Indian mustard (Brassica juncea 9 every 15 rows 

Monitoring: 

Regular scouting during seedling and shoot growth and during flowering and fruiting is very important. Inspect the underside of terminal leaves for egg masses and groups of small caterpillars at least once a week.

Prevention

  1. Apply Stopgel of the life cycle of the plant
  2. Ensure adequate growing conditions, such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. Maintain natural surroundings (trees, shrubs) attracts natural enemies 
  4. Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hoverflies.
  5. Clip off shoots that contain caterpillars while the insects are young and feeding in groups. 

Crop rotation: 

Rotate with maize, legumes, cabbages, carrots and onions.

Mixed cropping: 

Brassica should be intercropped with other crops. Onions, chillies and tomatoes can be intercropped with brassicas.

Trap Crops: 

Plant trap crops such as mustard and rape at the edges of the field to reduce DBM attack. 

Monitoring: 

Regular scouting during seedling and shoot growth and during flowering and fruiting is very important (at least twice a week, as they can rapidly increase). Small black and yellow flies may be detected flying closely around the crop or on the leaves. Inspection of the leaf surface will reveal punctures of the epidermis and the greenish-white mines in the leaves. Feeding maggots will be found at the end of the mine. When the maggots have already left the mine to pupate, the mine will end with a small convex slit in the epidermis. Occasionally the pupae may be found on the leaf surface, although in most cases they pupate in the soil. Leafminers can also be monitored by foliage examination for the presence of mines and larvae and by trapping adult flies with yellow sticky traps. Yellow sticky traps used for mass trapping can effectively control the pest at low densities.

Prevention

  1. Apply Stopgel of the life cycle of the plant
  2. Ensure adequate growing conditions Ensure for the crop such as good soils, adequate water supply, proper feeding, proper spacing and good nursery management to start the crops with healthy, vigorous plants
  3. maintain natural surroundings (trees, shrubs) attracts natural enemies 
  4. Avoid broad spectrum insecticides to conserve natural enemies such as parasitic wasps, ladybirds, lacewings and hoverflies.
  5. Weeds play an important role in harbouring whiteflies between crop plantings. They also often harbour whitefly-transmitted viruses. Therefore, weeds should be removed in advance of planting. Fields should also be kept weed free.

Mixed cropping: 

Common mixed cropping includes use of companion planting and intercropping.

  1. Intercropping tomatoes with capsicum and cucumber 
  2. Bordering the plot with coriander or fenugreek attract natural enemies and repels whiteflies. 
  3. Other repellents to whiteflies are nasturtium and Mexican marigolds
  4. Parsley attracts natural enemies as parasitic wasps

Nutrient Management: 

Avoid high levels of nitrogen in soil, as this causes plants to become succulent and attractive to aphids.

 

Monitoring: 

Regular scouting during seedling and shoot growth and during flowering and fruiting is very important. 

  1. Monitor at least 3 times a week for aphids early in the morning/late in day during dry periods.
  2. For early detection inspect for adults and eggs. They are usually found on young leaves. Watch out for whiteflies flying up when the crop is disturbed. 
  3. Yellowing, curling, crumpling of leaves occurs at heavy infestation.
  4. Whiteflies can transmit viruses, which cause virus disease. Leaves will have yellowish green mosaics

Small numbers of whiteflies do not cause major direct plant damage to healthy, mature plants and therefore do not justify any chemical intervention: Action threshold level is 10-20 plants with symptoms and/or at least 20 whiteflies on at least 10-20 plants/acre