Field evaluation of integrated pest management-compatible pesticides for the citrus leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae) and its parasitoid Ageniaspis citricola (Hymenoptera: Encyrtidae).

Potentially selective and integrated pest management (IPM)-compatible pesticides for the citrus leafminer Phyllocnistis citrella Stainton and its parasitoid Ageniaspis citricola Logvinovskaya were compared under nursery field conditions at Gainesville, FL. In 1996, replicated blocks of young grapefruit trees were treated with 2% petroleum oil and 1 x the lowest recommended field rate (LRFR) of diflubenzuron + oil (0.4%). Untreated and treated controls (avermectin at 1 x the LRFR + oil) were included. In 1997, blocks were treated with oil (3%), 1 x the LRFR of azadirachtin + oil, 1 x the LRFR of diflubenzuron + oil and 0.1 x the LRFR of avermectin + oil. Untreated and treated controls were again included. Oil at 3%, azadirachtin at 1 x the LRFR + 0.4% of oil, and diflubenzuron at 1 x the LRFR + 0.4% of oil were shown to be IPM-compatible pesticides. In 1997, these blocks had fewer mines per leaf and P. citrella pupae parasitized by A. citricola per total leaves sampled compared with the untreated control but more than the treated control (alpha = 0.05). Avermectin at 0.1 x the LRFR + 0.4% of oil was not considered an IPM-compatible pesticide because, while it reduced the number of P. citrella mines per leaf, it reduced the number of A. citricola to levels as low as the treated control. Actual P. citrella infestation levels had no detectable effect on tree growth and vigor. Pesticide applications were not justified when P. citrella infestations were < 1 mine per leaf and the biological control agent A. citricola was present.

Short-Term Flooding Effects on Gas Exchange and Quantum Yield of Rabbiteye Blueberry (Vaccinium ashei Reade).

Roots of 1.5-year-old ;Woodard' rabbiteye blueberry plants (Vaccinium ashei Reade) were flooded in containers or maintained at container capacity over a 5-day period. Carbon assimilation, and stomatal and residual conductances were monitored on one fully expanded shoot/plant using an open flow gas analysis system. Quantum yield was calculated from light response curves. Carbon assimilation and quantum yield of flooded plants decreased to 64 and 41% of control values, respectively, after 1 day of flooding and continued decreasing to 38 and 27% after 4 days. Stomatal and residual conductances to CO(2) also decreased after 1 day of flooding compared with those of unflooded plants with residual conductance severely limiting carbon assimilation after 4 days of flooding. Stomatal opening occurred in 75 to 90 minutes and rate of opening was unaffected by flooding.