Diaphorina citri vectors pathogens that cause ‘huanglongbing’ or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005–2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24–68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76–100% nymphs or adults over 99–296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on individual or regional assessment of all factors.

Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of the devasta

Tomato crops are susceptible to multiple diseases, several of which may be present during the same season. Therefore, rapid disease identification could enhance crop management consequently increasing the yield. In this study, nondestructive methods were developed to detect diseases that affect tomato crops, such as bacterial spot (BS), target spot (TS), and tomato yellow leaf curl (TYLC) for two varieties of tomato (susceptible and tolerant to TYLC only) by using hyperspectral sensing in two conditions: a) laboratory (benchtop scanning), and b) in field using an unmanned aerial vehicle (UAV-based). The stepwise discriminant analysis (STDA) and the radial basis function were applied to classify the infected plants and distinguish them from noninfected or healthy (H) plants. Multiple vegetation indices (VIs) and the M statistic method were utilized to distinguish and classify the diseased plants. In general, the classification results between healthy and diseased plants were highly accurate for all diseases; for instance, when comparing H vs. BS, TS, and TYLC in the asymptomatic stage and laboratory conditions, the classification rates were 94%, 95%, and 100%, respectively. Similarly, in the symptomatic stage, the classification rates between healthy and infected plants were 98% for BS, and 99–100% for TS and TYLC diseases. The classification results in the field conditions also showed high values of 98%, 96%, and 100%, for BS, TS, and TYLC, respectively. The VIs that could best identify these diseases were the renormalized difference vegetation index (RDVI), and the modified triangular vegetation index 1 (MTVI 1) in both laboratory and field. The results were promising and suggest the possibility to identify these diseases using remote sensing.

The development of insecticide resistance in Asian citrus psyllid, Diaphorina citri Kuwayama, populations is a serious threat to the citrus industry. As a contribution to a resistance management strategy, we developed a glass vial technique to monitor field populations of Asian citrus psyllid for insecticide resistance. Diagnostic concentrations needed to separate susceptible genotypes from resistant individuals were determined for cypermethrin (0.5 μg per vial), malathion (1.0 μg per vial), diazinon (1.0 μg per vial), carbaryl (1.0 μg per vial), carbofuran (0.1 μg per vial), methomyl (1.0 μg per vial), propoxur (1.0 μg per vial), endosulfan (1.0 μg per vial), imidacloprid (0.5 μg per vial), acetamiprid (5.0 μg per vial), chlorfenapyr (2.5 μg per vial), and fenpyroximate (2.5 μg per vial). In 2014, resistance to two carbamate insecticides (carbaryl and carbofuran), one organophosphate (malathion), one pyrethroid (cypermethrin), and one pyrazole (fenpyroximate) was detected in field populations of Asian citrus psyllid in Immokalee, FL. There was no resistance detected to diazinon, methomyl, propoxur, endosulfan, imidacloprid, and chlorfenapyr. The levels of insecticide resistance were variable and unstable, suggesting that resistance could be successfully managed. The results validate the use of the glass vial bioassay to monitor for resistance in Asian citrus psyllid populations and provide the basis for the development of a resistance management strategy designed to extend the efficacy of all classes of insecticides used for control of the Asian citrus psyllid.