First record of Cerchysiella insularis (Howard, 1897) (Hymenoptera: Encyrtidae) parasitizing Lobiopa insularis (Castelnau, 1840) (Coleoptera: Nitidulidae) on strawberries

Abstract

Strawberry is one of the most socially and economically important small fruits in Brazil, with strong demand by the food industry driving high levels of production. However, phytosanitary problems, especially insect damage, can hamper strawberry cultivation. A pest of great concern is the strawberry sap beetle, Lobiopa insularis (Coleoptera: Nitidulidae), which damages the fruits. Chemical control has not been effective against L. insularis, as it makes harvesting and marketing the product unfeasible. Parasitoids have been effectively utilized to control various strawberry pests and support sustainable production. We report the occurrence of the wasp Cerchysiella insularis (Hymenoptera: Encyrtidae) as a parasite of L. insularis on strawberries in São José dos Pinhais, Paraná, Brazil. Samples of strawberries (San Andreas cultivar) attacked by L. insularis were collected from February to March, 2019. Lobiopa insularis larvae were individually placed in rearing pots, fed on San Andreas strawberries, and checked weekly for symptoms of parasitism or parasitoid emergence. Parasitism rates were 33.85% in March and 45.90% in February. The sex ratio varied between 0.88 and 0.86. All parasitized larvae were infested by C. insularis. The natural parasitism rate above 33% and high sex ratio of C. insularis in strawberry crops indicated that it may have the potential in the control of L. insularis.