Incidence of citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), and its natural enemies on grapefruit in protected and open production systems

Citrus Under Protective Screen (CUPS) is a strategy used to protect citrus from pests and diseases, mainly Asian citrus psyllid, Diaphorina citri, and its vectored huanglongbing disease. However, pests such as mites, thrips, scales, and citrus leafminer (CLM) Phyllocnistis citrella Stainton are expected in the CUPS. In 2019, populations of CLM and its natural enemies were studied in the CUPS and Open Area (OA) control at the University of Florida’s Indian River Research and Education Center, Fort Pierce, FL. Four CUPS and controls contained ‘Ray Ruby’ grapefruit (Citrus paradisi) trees on Sour Orange and US897 rootstocks planted in-ground and pots. CLM males captured in the pheromone traps were two to three-fold fewer in the CUPS than OA. Significantly more CLM males were captured in the trees planted in-ground than pots in the CUPS, but there was no difference in the OA. CLM larval populations were less in the CUPS than OA. Within CUPS or OA, there was no significant difference in CLM larval populations between rootstocks or planting systems. Pnigalio minio and Ageniaspis citricola dominated the parasitoid complex of CLM in CUPS and OA. Parasitism rates were low in the CUPS than OA, averaging 5.3 to 12% and 21 to 44 %, respectively. Predators included ants, spiders, lacewings, and ladybeetles and were less in the CUPS than OA.