Insecticides used in agricultural pest management pose survival risks to the stingless bees that forage on crops in tropical and subtropical regions. In the present study, we evaluated, under laboratory conditions, the acute oral toxicity of five selected insecticides (dinotefuran, imidacloprid, flupyradifurone, spirotetramat, and cyantraniliprole) to two species of neotropical stingless bees: Nannotrigona perilampoides and Frieseomelitta nigra. At field recommended doses, dinotefuran, imidacloprid, and flupyradifurone caused the highest mortality in both bee species. These insecticides also caused the largest decrease in the survival rate when exposed to a 10-fold dilution of the field recommended doses. Notably, dinotefuran exerted a high effect even at 100-fold dilution (100% mortality). In contrast, cyantraniliprole had a low effect and spirotetramat was virtually nontoxic. These results suggest that some insecticides used to control sap-sucking insects may have a significant negative impact on the communities of stingless bees.

Background. The use of biostimulants is an alternative to improve the growth and productivity of horticultural crops. Objective. To evaluate the effect of three biostimulants (seaweed extracts, humic acids and amino acids) on the plant growth, foliar characteristics, and population density of Bemisia tabaci in habanero pepper plants (Capsicum chinense). Methodology. The biostimulants were applied to the plant growth substrate in seedling and in pot plants. The response variables were plant growth, leaf thickness and toughness, leaf area and population density of B. tabaci. Results. Humic acids promoted the number of leaves and stem thickness in seedlings. The thickness of the leaves was stimulated by seaweed extract and humic acids and the leaf area by amino acids. The biostimulants had no effect on the response of the plants to the population density of B. tabaci. Implication. The use of biostimulants in habanero pepper plants could enhance plant growth in specific growth phases. Conclusion. The use of biostimulants in habanero pepper plants did not show consistent effects on plant growth promotion in habanero pepper. There were no effects of the biostimulants on the induction of plant defense to B. tabaci in habanero pepper.

Background. The whitefly Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae) is a pest that causes significant losses in field and greenhouse crops worldwide. Objective. To evaluate the incorporation of biorational and chemical insecticides on the population density of whitefly Bemisia tabaci, fruit yield and fruit quality in tomato. Methodology. Three pest management treatments were included: Biorational (botanical insecticides and insect growth regulators), Biorational-Intermediate (botanical insecticide and chemical insecticides) and Conventional (conventional chemical insecticides). Results. Overall, the population density of B. tabaci was low from the time when the pest-exclusion floating net was removed to the sampling periods 61 to 78 days after transplant (dat). However from 92 to 108 dat, the population density of inmature and adults increased dramatically. The treatment Conventional was the most effective to supress the population density of B. tabaci when they were low, but when an increase in population density of B. tabaci ocurred, the treatment Biorational-Intermediate was the most effective. The population density of eggs and nymphs on plant leaves were similar among treatments. The fruit yield and overall the bromatologic characteristics of fruits were not significantly different among treatments. Conclusion. The treatment Biorational-Intermediate would represent a feasible strategy to manage Bemisia tabaci in tomato crops.

This study evaluated the acaricidal effects of biosurfactants produced by Serratia ureilytica against the two-spotted spider mite Tetranychus urticae and their compatibility with the predatory mite Ambliseus swirski. The biosurfactants were obtained via liquid cultures of the bacterial strains. In the laboratory, T. urticae was exposed via acaricide-immersed leaves and A. swirskii via acaricide-coated glass vials. In the greenhouse, mite-infested plants were sprayed with the biosurfactants. In the laboratory, biosurfactants produced by S. ureilytica NOD-3 and UTS exhibited strong acaricidal activity, causing 95% mortality in adults and reducing egg viability by more than 60%. In the greenhouse trial, all biosurfactants significantly suppressed T. urticae populations at all evaluated periods (7, 14, and 21 days post-application). Gas chromatography–mass spectrometry (GC-MS) analysis of the biosurfactants identified several fatty acids, including hexadecanoic acid, pentanoic acid, octadecanoic acid, decanoic acid, and tetradecanoic acid, as well as the amino acids L-proline, L-lysine, L-valine, and glutamic acid. These fatty acids and amino acids are known structural components of lipopeptides. Furthermore, the bioinformatic analysis of the genomes of the three S. ureilytica strains revealed nonribosomal peptide synthetase (NRPS) gene clusters homologous to those involved in the biosynthesis of lipopeptides. These findings demonstrate that S. ureilytica biosurfactants are promising eco-friendly acaricides, reducing T. urticae populations by >95% while partially sparing A. swirskii.