By Francis Ndungu
A small-scale avocado export farm is using lightbulb-lit tins of used diesel oil to get rid of the false codling moth, which had been savaging export volumes.
The farm manager of Ibis Farm in Timau, Martin Wango, started using this cheap technology in 2023 after they lost 2,100 pieces of hass avocado to the destructive pest.
The false codling moth is a quarantine listed pest by the European Union (EU) and fruits entering the region have to be inspected for the moth. This however leaves farmers in a double bind; it requires heavy pesticide application to control right before harvest but this also risks getting the fruits barred from the EU for having heavy pesticide residue.
Martin, an agricultural officer by training, explained that the use of old engine oil stems from a chance discovery. “We realised that every morning, we found so many moths floating dead on the old engine oil left in drums after we serviced our tractors. They were unable to move because of the sticky oil.
FCM can wipe out entire avocado farms. The moth kills fruit before they mature by feeding on it internally causing it to weaken and fall. It also digs holes which have a white powder coming out of them affecting the quality of the fruits. It is listed as a quarantine pest by the European Union. This means EU countries must inspect some of the fruits, flowers and vegetables entering the country for the moth.
The illuminating light from the tractor shed attracted the FCM at night. As they flew and mate around the bulb which is near the drums containing the oil they fell inside and died due to suffocation,“ he explained.
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Because this happened on a daily basis, I found that so many false codling moths died and, as a result, decided to improvise this method for FCM control in our one-acre hass avocado farm.
“Since we started using the old oil and lightbulb method of dealing with FCM we have had a great turn around in the amount of fruits we not only harvest but also sell. At the airport, we used to have more than 2,100 pieces of hass avocado rejected due to chemical residue and pest infestations. We were producing 3,500 pieces in 2023, but after adopting this new method of pest control, production has hiked up to 8,800 pieces of quality fruits. The level of pests reduced by 60 per cent, making our production process smooth,” he explained.
The false codling moth bores holes in tender avocado fruits, lowering the quality of the fruits and causing their rejection at the market. It also feeds on leaves, making the plant unable to make its own food, which leads to the reduced size of the fruits. The moth also raises the cost of production because farmers have to spray pesticides twice a wee,k which is very expensive.
“Before, we used pesticides that were very costly, such as sticky trap cards and pheromones. The traps could only manage a few of the moths, but most of them were not caught. Pesticides are also not reliable and can kill even useful insects such as bees which are essential in the pollination of avocado trees. Occasionally, the pesticide also caused flowers and fruit abortion if spraying was done during high temperature, reducing the number of fruits we got. The moths becoming pest resistant was also a major concern for us. They also led to the rejection of the fruits at the airport where the fruits were found to have a high amount of chemical residue. Since we adopted this new method, my cost of production has reduced plus the materials used are readily available,” Martin explained.
Since the moth mostly attacks at night, it was very difficult for Ibis farm to control it.
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“We cut a twenty-litre gallon into two halves and put it out. The containers are filled slightly with the old engine oil. At 10 pm, they are hung over a tree with a lamp slightly above the gallons. The FCM and other pests are attracted to the light, and they tend to surround the illuminating light; they fly around it vigorously and fall inside the gallon and die. The old engine oil can be recycled as many times as possible as long as the dead pests are regularly sieved,” explained the farm manager.
Old engine oil is capable of controlling so many other pest,s including thrips, white flies and adult caterpillars. There are also labour cost savings since no employee is required to spray pesticides. The method also operates well at night thus no interferences on the day to day activities in the farm since no time is wasted as employees wait for chemicals to be sprayed.