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Arbuscular mycorrhizal fungi (AMF) develop strong mutualistic associations with roots of about 70% of all vascular plants. By modifying host plant nutrient uptake, growth and defense, AMF also indirectly influence the aboveground herbivorous insect community. Since plant response to AMF depends on the extent of mycorrhization, outcomes of the bottom-up effects of AMF on herbivores are extremely variable and not well understood. We thus tested whether the generalist phloem feeder Bemisia tabaci (tobacco whitefly) was affected by the colonization of habanero pepper seedlings (Capsicum chinense) by different densities of the AMF Rhizophagus irregularis. After AMF inoculation (with control, low and high doses of liquid inoculum), seedlings were grown in a greenhouse without (control) and with whiteflies (10 adults per seedling). We measured plant traits and growth and biomass allocations at 2, 16 and 30 days after transplantation of emerged seedlings. We estimated whitefly adult, egg and nymph densities 28 days after transplantation. B. tabaci abundance significantly increased after C. chinense inoculation with low AMF density (120% increase for adults, 97% for eggs) through an augmentation of seedling nutritional status. By enhancing plant tolerance and primary metabolism, the higher density of AMF did not affect B. tabaci fitness on seedlings. We highlight here that whitefly abundance on mycorrhizal C. chinense varies widely depending on AMF inoculum concentration.

Objective: To evaluate the phenological development and fruit quality of habaneropepper (Capsicum chinense Jacq.) with three nutrient solutions.Design / Methodology / Approach: In a hydroponic system the nutrient solutionsof Steiner, Hoagland and Soria were used to evaluate the phenology, morphologyand pungency (spicy-hotness) of the habanero pepper fruits.Results: It was observed that the nutrient solution of Soria brought flowering 4 dahead, but it delayed fruiting by 2 d compared to the other treatments. Steinersolution incremented length (4 cm), diameter (2.9 cm), weight (8 g) and moisturecontent (89%) of the fruit compared to the other nutrient solutions. Capsaicin anddihydrocapsaicin increased in plants watered with Steiner nutrient solutions (24and 12.5 mg g -1 , respectively) and Soria (23 and 12.7 mg g -1 , respectively), as wellas Scoville units (> 538,000).Study limitations / Implications: Although favorable results were found in sometreatments, more studies are required to evaluate the nutrient composition of thedifferent organs of habanero pepper plants, by phenological stages.Findings / Conclusions: Considering phenology, fruit quality and capsaicinoidscontent, the Steiner nutrient solution could be a suitable option for cultivatinghabanero peppers in hydroponic systems.

The excessive application of organophosphate pesticides (OPPs) in crop fields close to hives and its application in beekeeping practices are potential sources of contamination of propolis. Pesticides were extracted from raw propolis by matrix solid-phase dispersion. Because of the complex chemical composition of propolis, binary solvent mixtures based on acetonitrile and a relatively non-polar solvent in different proportions were tested for the selective elution of OPPs. The effect of mixed solvents on clean-up was evaluated by GC-MS and the main interfering compounds co-eluted with pesticides were identified. In addition, three volumes of the solvent mixture and the volume of the sample were evaluated in an experimental factorial design. The final experimental conditions were 1 mL of dissolved propolis and 8 mL of acetonitrile/dichloromethane (g4 r = 25: 75). Mean recoveries ranged from 55 % to 96 % (relative standard deviation < 8 %) with an inter-day precision lower than 24 %. The proposed method was applied to the analysis of real samples obtained from local beekeepers.