Twig borer puts coffee yields under threat

Coffee, in especially central and south western Uganda, is under threat of a pest known as the black coffee twig borer. In many areas, it is present in almost all the fields.

“In each district, we visit 10 farmers and estimate the farms infested. We conducted a survey in 26 districts. Most affected were Rakai, Butambala, Bukomansimbi, Lwengo and Kayunga, Mpigi, Wakiso and Mitooma then Kanungu and Rukungiri, Kibaale and Sembabule,” explains Dr Godfrey Kagezi , an entomologist.

First sign
He is part of team from Usaid-Livelihoods and Enterprises for Agricultural Development (LEAD), which was on a 15-district sensitisation programme.

“In these districts, prevalence is 100 per cent. When we look at the damage, the primary branches are infested, which are the ones that carry the berries. When the twig dries, the cherries are lost hence volumes of harvests are affected and incomes lost,” he adds.

The first sign of the presence of the borer is a characteristic pin-size hole on the twigs. Then there is yellowing, wilting and drying of leaves and twigs. Dr Kagezi says, “When you dissect the twig, you will find the adults and the various stages like larvae, eggs, and pupa.”
Mr William Lubo, chairman of Rakai District Coffee Stakeholders Platform, brings together 30,000 farmers, reveals the black coffee twig borer has affected these farmers for five years.

How to handle
“Many confuse it with coffee wilt. The other is a disease and this one is an insect. This is largely because of the way they manifest themselves. Wilt dries the plant but it starts from up but the borer starts with the twigs.”

Under the LEAD project, the farmers were taught how to handle the twig borer. “With wilt, we cut down the whole tree and burn it,” Lubo explains. “When the twig borer attacks the tree, we have been taught to break off the affected twig and burn it. Alternatively, we can spray the affected tree.”

Robert Ssentamu, Uganda Coffee Development Authority’s (UCDA) regional extension officer, points out that the pest was first heard of in Kamwozi, Buwunga sub-country. “A farmer reported that his farm had been attacked by this insect. We had heard of it in Mukono, Bushenyi and Bundibugyo,” he recollects.
Dr Kagezi adds, “It has many alternate hosts. Worldwide, it is said to attack more than 240 plant species. In Uganda, it is confirmed it on more than 40 plant species.”

Proper choice
These include Robusta and Arabica coffee, tea, cocoa, food crops like egg plants, trees like eucalyptus, Maesopsis eminii, locally known as musizi, shade trees especially albizia chinesis, fruit trees like avocado, jackfruit, mangoes, and shrubs like calliandria.

Management of the borer calls for daily inspection of the coffee fields. Any infested parts should be cut and burnt immediately. 
“There is need for a proper choice of shade trees. Avoid Albizia chinesis, musizi and musambya. We have found most of the damages on these. And they exhibit the same signs when the beetles infest them,” Kagezi advises.http://www.monitor.co.ug/Magazines/Farming/Twig-borer-puts-coffee-yields-under-threat/-/689860/1757006/-/qo4efaz/-/index.html