This experiment demonstrated that vector control, especially when combined with enhanced foliar nutrition, could significantly increase yields in a citrus orchard with high incidence of HLB. Economic thresholds for both insecticide and nutrient applications are needed under different market and environmental conditions.

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Intensive insecticide and nutrient management have been attempted worldwide to reduce citrus huanglongbing (HLB) symptom development and yield loss. However, effects of insecticide and nutrient applications on HLB have been poorly understood. Leaf nutrients, jasmonic and salicylic acid contents, cycle threshold (Ct) values of Ca. Liberibacter asiaticus (Las), and community structure of endophytic α-proteobacteria were evaluated after insecticide treatment, 'nutrition' treatment (including systemic resistance inducing agents), or both in comparison with a control in a two-factor field experiment in 2008-2012. Leaf N, Mn, Zn and B significantly increased whilst Cu decreased after nutrient applications. Salicylic acid significantly increased in old leaves treated with insecticides, nutrients or both, and in young leaves treated with nutrients only. The jasmonic acid concentration was highest after the nutrition treatment in both old and young leaves. Ct values of Las and leaf area and weight significantly increased after long-term nutrient applications in 2011 and/or 2012. Redundancy analysis of the endophytic α-proteobacteria community structure indicated that the communities were mainly separated according to nutrient applications, which were positively associated with Ct values of Las and Ca, Mn, Zn, B, Mg, and Fe contents in leaf samples collected in 2012. Thus, effects of insecticides on HLB were significant in the early 2-year period whilst nutrients had significant effects on Las content and leaf size and weight after at least 3 years of application.

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BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

The dispersal behavior of flower thrips was studied during two field seasons within blueberry (Vaccinium spp.) plantings in Florida and southern Georgia. A "shake and rinse" technique used to extract thrips from inside the blueberry flowers was not significantly different from the conventional dissecting technique, but the time taken to complete the extraction of thrips was significantly shorter. Overall, the highest concentration of thrips was captured inside the canopy of blueberry bushes. Using a grid of traps to monitor the dispersal of thrips during the blueberry flowering season, we analyzed their dispersion with graphical and analytical methods to determine and describe their distribution within blueberry plantings. Thrips began to form "hot-spots" 5-7 d after bloom initiation. A hot-spot is defined as a large number of thrips concentrated in a small area of the field, whereas the rest of the field has a low population. The behavior of the population inside these hot-spots fit a Gaussian tendency and a regression was conducted to describe this tendency. Green's and Standardized Morisita's indices were used to determine thrips level of aggregation. Results showed significantly aggregated populations of thrips in both years. Formation of hot-spots in blueberry plantings seemed to be random. However, the formation of hot-spots was higher in places where more than seven thrips per day were captured on sticky traps, 5 to 7 d after the bloom begins. With these results, producers will be able to monitor thrips populations and locate and manage hot-spots before they become a more serious a problem on blueberry farms.

Survival of Geocoris punctipes Say adults following exposure to azadirachtin, spinosad, thiamethoxam, diazinon, and imidacloprid was assessed in laboratory assays and greenhouse tests. In the laboratory assays, adults were continuously exposed for 48 h to filter papers treated with the individual insecticides. Survival was greatest following exposure to the untreated control (100 ± 0.0%), azadirachtin (95.0 ± 2.2%), and imidacloprid (81.7 ± 7.9%). Mean (± SEM) survival following exposure to spinosad (55.0 ± 11.2%) and thiamethoxam (46.6 ± 3.3%) was significantly lower, whereas diazinon killed all adults within 12 h of exposure. In the greenhouse tests, adults were continuously exposed to bush beans, Phaseolus vulgaris L., foliage treated with the individual insecticides. Mean (± SEM) survival following 144 h of continuous exposure to treated foliage was 97.5 ± 2.5% for the untreated control, 92.5 ± 5.3% for azadirachtin, 92.5 ± 3.7% for diazinon, 72.5 ± 8.4% for imidacloprid, 70.0 ± 8.4% for spinosad, and 57.5 ± 8.8% for thiamethoxam. Statistically significant differences were observed with thiamethoxam versus diazinon, azadirachtin and the control. The results for the filter paper assay and the greenhouse tests are encouraging in terms of potential natural enemy conservation in IPM programs employing these insecticides.

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