Artrópodos asociados a diferentes genotipos de cacao (Theobroma cacao L.)

Abstract

Cacao (Theobroma cacao L.) is a crop in great demand, since the beans are used to produce chocolate, which presents various characteristics both in flavor and in health benefits. Ecuador is a producer and exporter of cocoa, so the management of the crop is intensified and causes the loss of biodiversity. The main objective of this research was to identify the arthropods associated with different cacao genotypes. The study was carried out in a 2800 m2 plot of cocoa designed in random blocks with three repetitions located at the Faculty of Agricultural Engineering, Technical University of Manabí. In the lot there are 24 cacao materials, including the national type and the CCN-51, of which four combinations (pattern/graft) were chosen (EET-339/EET576, IMC-67/EET484, EET-400/EETP- 800 and POUND-12/CCN-51), each combination had four cacao plants planted. Leaf samples were taken to identify populations of aphids (Toxoptera aurantii) and mealybugs (Dysmicoccus sp.). Yellow traps were also placed to identify the number of individuals per family of phytophagous insects, parasitoids and predators. Alcohol traps were used to identify scolytines taxa and ear evaluation in the field was performed to establish ear damage by bugs of the genus Monalonion. Four taxa of scolytines Hypothenemus sp., Xyleborus affinis, Premnobius sp., Corthylus sp. On the leaves, Toxoptera aurantii was significantly higher than the EET-399/EET-576 genotype and the number of mealybugs of the genus Dysmicoccus was low and did not differ between genotypes. In the traps, the most abundant phytophagous families were Chrysomelidae and Membracidae. For natural enemies, important families of predators such as Coccinellidae, Dolichipodidae and Vespidae were observed. Six families of parasitoids were present associated with cacao genotypes. The EET-400/EETP-800 genotype exhibited the highest number of ears damaged by bugs of the genus Monalonium, reaching 25% damage, and the highest damage scale with grade 3 was also observed. These results represent a significant contribution to the knowledge of the entomofauna associated with cocoa that until now has been little studied in Ecuador. It is suggested that future studies focus on measuring the effects that scolitins can cause in cacao, and the role played by the families of predators and parasitoids found.