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The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a worldwide pest of citrus crops and is responsible for proliferation of citrus bacterial canker, Xanthomonas axonopodis (Hasse) pv. citri (Gamma Proteobacteria: Xanthomonadaceae). We developed and evaluated an attracticide formulation, termed MalEx, for control of P. citrella. MalEx is a viscous paste with UV-protective properties that is dispensed as 50-μl droplets using custom-made calibrated pumps. A formulation containing 0.016% P. citrella pheromone [3:1 blend of ( Z, Z, E)-7,11,13-hexadecatrienal and ( Z, Z)-7,11-hexadecadienal] and 6% permethrin was found to suppress male response to pheromone in the field better than formulations containing 10× less pheromone. Although formulations without permethrin showed some suppression of male activity because of mating disruption, addition of 6% permethrin to the formulation was required for optimal efficacy. When MalEx, containing 0.016% pheromone and 6% permethrin, was applied at 3 000 point sources ha−1, the application height did not influence efficacy of male P. citrella suppression within mature 4-m tall citrus trees. Decreasing the rate of MalEx from 3 000 to 1 500 droplets ha−1 reduced efficacy as measured by both male P. citrella activity and larval infestation. Although 4 500 droplets ha−1 did not result in statistically better efficacy than 3 000 droplets ha−1, there was a noticeable trend for higher efficacy as droplet density increased. Continuous treatment of 0.5-ha blocks of citrus with MalEx over the course of 112 days reduced larval infestation of new flush, as compared with those in untreated control plots, by 3.6–7.2× depending on droplet application density. In laboratory behavioral bioassays, the attractiveness of MalEx droplets to male P. citrella was drastically reduced after 21 days of field aging. However, our laboratory investigation confirmed that 100% of males contacting MalEx droplets, aged up to 35 days in the field, were killed within 24 h. Direct observation of male P. citrella behavior in the field confirmed that attracted males made contact with droplets. Control of P. citrella with MalEx should reduce the number of required broad spectrum sprays for leafminer management in both field and citrus nursery settings. [ABSTRACT FROM AUTHOR]

Population density of citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), was monitored in a Florida citrus grove for 5 years by scouting weekly for larval-induced mines (leafminer-created tunnels in the leaves) in a replicated citrus plot treated with seven insect control regimes: Admire (imidacloprid) applied at 12, 6, 3, or 2-month intervals; Temik (aldicarb) applied annually; Metasystox-R (oxydemeton-methyl) applied annually; or no insect control. Leafminer populations were highest during the warmer months (April to September) and lowest during the cooler months (November to March). Populations peaked during June in all 5 years monitored. Trees treated with Temik or Metasystox-R had the same number of mines as the untreated controls. A biannual treatment with Admire reduced leafminer damage (number of mines) all 5 years compared with the controls. Additional Admire applications further reduced damage during some, but not all, years. A single application of Admire significantly reduced mines in 3 of the 5 years. [ABSTRACT FROM AUTHOR]

Citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is one of the most important insect pests of Pakistan's citrus nursery stock and caused extensive damage to young flushes. The organic compost is a widespread technique used to manage insect pests and plant diseases. Different composts (biofert, tara root and vermicompost) at 0.5 and 0.25 kg/plant concentration in comparison to NPK fertilizer at 0.4 and 0.2 g/plant were evaluated for CLM infestation and the associated citrus canker disease in nursery plantations of Citrus reticulata Blanco. Application of biofert at 0.5 kg/plant reduced the CLM infestation up to 54.5% during Fall-2016 and 39.1% during Summer-2017 in comparison to control treatment. The CLM larval density was also found lower by the application of biofert followed by vermicompost during both seasons. Both concentrations of biofert followed by vermicompost at 0.5 kg/plant resulted in remarkable protection against citrus canker disease in both flushes. The incidence of canker associated with CLM infested leaves was also studied and found lower by the application of biofert and vermicompost compared with control treatment. Conclusively, the soil amendment using biofert and vermicompost affects the CLM population and canker infection in nursery plantations. These organic fertilizers can be used in future citrus IPM programs as a tool to suppress the CLM population and citrus canker disease. [ABSTRACT FROM AUTHOR]