By The Organic Farmer Magazine,
Farmers are advised to start spraying their maize crop from two (2) to three (3) weeks after planting. They should use simple biopesticides such as plant extracts to control fall armyworm and other pests.
The fall armyworm has the ability to develop resistance to pesticides. It spreads fast and attacks many crops compared to other pests. Spraying of both organic or chemical pesticides when the pest is beyond the third instar (third stage) has very little effect on it.
The adult moth lays eggs inside the plant and only at night. This becomes difficult to detect the pest. The newly hatched larvae also develop inside the plant and within a few days, it moults into the third stage which is very difficult to control. By this time, it is too late to save the plant. Therefore, spraying should be done at the second instar (larvae) stage to kill the larvae. Early pest detection helps the farmer to assess the situation and plan how to manage the pest in order to eradicate it.
Monitoring involves observing early warning signs of pest infestation on the crops. Pre-monitoring can be done by setting up pheromone-baited traps at the household level. Surveillance helps the farmers to know when to start applying the pesticides. It is advisable to spray your crops two (2) weeks after planting, at knee height and at tasselling stages (see sketch above). It is also recommended to spray early in the morning or late in the evening and when it is not windy to avoid wastage of pesticides. In addition, most of the chemicals in the market cannot kill eggs. For the pesticide to be effective, the farmers need to scout in their maize crop and spray when the pest is at the larvae stage. They are also advised to use cheaper and less dangerous chemicals which are effective and are locally available. Most farmers practise farming as the sole source of their income. Any additional operating costs will reduce the anticipated yields and affect their incomes.
Other pest control measures
• Practise early planting to reduce the pest incidence.
• Maintain a healthy ecosystem to help in biological control as they harbour parasitoids (natural enemies) and birds.
• Use of biological control methods such as natural enemies and bacterial insecticides (Bacillus thuringiensis) has also been proven to be effective. For organic farmers, neembased biopesticides (Nimbecidine) are effective because they have anti-feedant properties and they reduce the capacity of the pest to lay eggs.
• Garlic-based biopesticides are also effective and work the same way as neem.
• Use of traps can also reduce the male moths and reduce its multiplication.
Finally, farmers should know that the fight against the fall armyworm requires an Integrated Pest Management (IPM) approach where several options are employed. There is no control method that can work alone. These control measures combined enable a farmer to have few pests which subsequently reduce the damage to the crop.
Natural method to control pests
Farmers across the country last year experienced the damage to their maize crops brought by the fall armyworm (a new invasive pest). As the government rushed to buy and recommend expensive chemical pesticides; most farmers were shocked to discover that the pest did not respond to the expensive chemicals they were using to control the pest.
However, as we advised then, it is a waste of money to use expensive chemicals for the control of fall armyworm. Farmers can keep away the pest by using simple organic plant extracts through proper timing.
Organic plant extract
Here is a simple method to prepare plant extracts to control the pest:
• Get 4 kg of different plants that can kill both pests and provide nutrients to your maize crop. Such plants are chillies, garlic, stinging nettles, tithonia, neem, African marigold, sodom’s apple, pyrethrum or lantana camara. • Mix molasses and EM1 (the two can be bought at your local agrovet shops). Add 5 litres of water. Dissolve a bar soap into the solution.
• Chop the plants into small pieces and put them into a bucket.
• Fill the bucket with water to the brim and close it completely to stop the air from escaping. Cover the mixture for 14 days.
• After 14 days, use a piece of cloth to filter the solution if you want to use a knapsack sprayer (this stops particles from blocking the nozzles).
• Dilute the mixture at a ratio of 1 litre of the solution to 100 litres of water.
How to spray
• Since organic plant extracts do not work the same way as chemical pesticides, ensure you spray your crop two (2) weeks after germination and then two (2) or three (3) times every week to protect your crop effectively. • Do not wait until you see the damage from the pest to start spraying.
• By spraying regularly, your crop will be protected from all pests including the fall armyworm.
How to use the knapsack sprayer effectively
Before selecting the sprayer to use, check the label and the guidelines for the pesticide, the recommended application rate, the type of equipment best suited for the application, the style of nozzle and other information for best results. • Always walk at the same speed used when calibrating the sprayer.
• Always ensure an even walking speed.
• Pump at an even rate while spraying. Hold nozzle at constant height above ground using a string and stone. • If spraying the entire field, first mark out the plot in swath widths with marking sticks to ensure there is a target to walk to, this will ensure even application.
For more information on natural pest control http://www.infonetbiovision.org/natural_pest_control