Cocoa agroforests can support biodiversity but the intensification of farming is degrading agroforests and affecting ecosystem services such as biological pest control.

Elites TV reports on an article in PlosOne about a study of 20 agroforests linking the shade index from eight vegetation variables with insect pests and beneficial insects (ants, wasps and spiders).

The study shows “the importance of a diverse shade canopy in reducing damage caused by cocoa pests,” says the article.

Scientists found that the number of spider webs and wasp nests significantly decreased with increasing density of exotic shade trees. However, a higher number of spider webs and wasp nests were found when there was a greater species richness of native shade tree species.

Cocoa yields were shown to be higher when shade and herb covers were less than 50 per cent. With increasing shade, fewer herbivore species (mirid bugs and cocoa pod borers) were found and the rate of herbivory on cocoa pods reduced.

Read the full story: Shade Tree Diversity, Cocoa Pest Damage, Yield Compensating Inputs and Farmers’ Net Returns in West Africa