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Se reportan los primeros registros de dos especies de hormigas, i.e., Hypoponera opacior y Pseudomyrmex seminole y dos géneros, i.e., Acanthosticus y Mycetosoritis (Hymenoptera: Formicidae), asociados a etapas de descomposición de necrotrampas colocadas en una zona semiurbana del estado de Yucatán, México.

The silverleaf whitefly (Bemisia tabaci) is the most harmful pest for vegetables in tropical zones. One alternative for its ecological management is the use of repellent aromatic plants. The hypothesis of this study is that the aromatic plants that diminish the attraction of B. tabaci to tomato have the capacity to prevent the infestation of this pest in the tomato crop when an intercropping system of tomato-aromatic plant is established. The objective of this study was to evaluate by means of the technique of olfactometry, the response of B. tabaci to the volatiles emitted by the crushed leaves of tomato and by the combination tomato + aromatic plant. The aromatic plants with highest activity in the olfactometry tests were intercropped in a tomato crop in the field. In the bioassays of olfactometry, a significant decrease was observed in the attraction of B. tabaci to crushed leaves of tomato + some aromatic plants compared with the attraction to tomato alone. The repellence indices (IR) showed that the aromatics Lavandula angustifolia Mill. (IR, 0.1), Petiveria alliacea L. (IR, 0.48), Petroselinum crispum Mill. (IR, 0.28) and Thymus vulgaris (IR, 0.5) had the greatest effect as repellent of adults. By integrating these aromatic species through intercropping in the tomato field crop, no significant difference was observed in the population density of eggs and adults of B. tabaci in the tomato foliage in regard to what was observed in the control (only tomato). The incidence and severity of viral symptoms did not decrease from the presence of the aromatic species intercropped in the tomato crop.

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.