Agony of farmers forced to clear plantation over papaya mealybugs

Paul Kibet watched helplessly as papaya mealybugs ravaged his two-acre pawpaw farm in the Perkerra Scheme, a crucial income source for local farmers. Despite using pesticides, the mealybugs continued to devastate his crops. When Smart Harvest visited in February, the farmers’ struggle was clear. By May, Kibet and others hoped for relief from a new biological control solution provided by the Centre for Agriculture and Bioscience International (CABI).

Kibet had hoped the biological control would stop the mealybugs, which left his pawpaw plants covered in a white residue. “Cutting down the plantation was the hardest decision I’ve ever made,” Kibet said. Despite initial resistance, he eventually cleared his farm after the intervention failed.

Dorcas Lekesio, Kibet’s neighbour, faced a similar plight. After introducing the biological control, she was forced to switch to tomatoes on her three-acre farm when the pawpaw plants did not recover. Previously, Lekesio harvested 10-15 bags per acre weekly, but a pest invasion in March caused the fruits to dry out. She regretted relying solely on the biological control and had to clear her farm, abandoning her pawpaw venture. 

Dr Selpha Miller a postdoctoral Centre for Agriculture and Bioscience International (CABI) pinning the Lavae of predator Wasps at a Pawpaw fruit tree who will feed on papaya mealybugs at Dorcas Lekesio Pawpaw farm at Perkerra irrigation scheme. [Kipsang Joseph, Standard]

Moses Kimutai, another farmer, also had to cut down his pawpaw trees after the mealybug invasion. He now focuses on vegetable farming, lamenting the loss of his primary income source and the employment it provided.

In contrast, Hassan Waswa’s pawpaw farm, a few kilometers from Lekesio’s, remains healthy and free from spots. Waswa continued spraying his crops despite the high cost and was determined to persist, though he remains uncertain about the future.

Vincent Abuje, the County Director of Agriculture, noted that they hadn’t received formal complaints from farmers, complicating their response to the issue.

Dr Selpha Miller from CABI explained that the papaya mealybug, an invasive pest from Central America and Mexico, invaded Kenya in 2016. CABI introduced a tiny wasp (Acerophagus papaya) from Western Africa in 2019 to control the mealybug. This biocontrol has proven effective in the Coast region, benefiting around 301 farmers.

The biocontrol was recently released in Perkerra. Dr Miller emphasised that while pesticides have immediate effects, the biological control requires time to establish. She advised farmers to avoid insecticides and be patient for about six months.

 “We were also encouraging farmers to avoid the use of insecticides on papaya trees as they will kill the parasitoids, for effective control of the pest, we advise farmers to be patient for about six months,” she said.  

From my recent follow-up at the coast after two years of release in July this year, she said the pest has been managed and the farmers no longer use insecticides.

Miller noted that Papaya infestations on all the farms surveyed were low and farmers have been able to harvest more papaya.

She advised farmers to reach out to the County Agricultural contact person and extension officer to keep encouraging the farmers to be patient and use the pesticides judiciously so that the parasitoid can be established and naturalized since within one month the parasitoid would not yield any results.

According to the CABI website, Scientists from CABI’s regional centre for Africa in Nairobi have recently deployed Acerophagus papaya, an environmentally friendly and safe-to-use biological control agent in the inland Kenya counties of Machakos, Makueni, Embu, Tharaka Nithi and Baringo, where smallholder farmers are affected by the pest.