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Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae) is an important grapevine pest in Europe recently encountered in America. Trichogramma cacoeciae Marchal (Hymenoptera: Trichogrammatidae) is amongst the most effective parasitoids for Lepidopteran species. Studies to evaluate the effect of kaolin, an inert, nontoxic mineral, on oviposition, egg hatch, and neonate mortality of these species were carried out. Efficacy on L. botrana neonate larvae, oviposition, and egg hatch was evaluated. Effects of kaolin on parasitism and emergence of T. cacoeciae from L. botrana and Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs were also evaluated. Lobesia botrana egg hatch and oviposition rates were reduced, and neonate larvae mortality was significantly greater in kaolin-treated arenas and when included in synthetic neonate larvae diet. Kaolin had no effect on T. cacoeciae parasitism in both hosts. There was only a slight but statistically insignificant effect on T. cacoeciae progeny emergence from L. botrana eggs and no effect from E. kuehniella. The results involving reductions in L. botrana oviposition and egg hatch and increase in larval mortality with kaolin suggest this compound may contribute to reduction in population densities and can be considered in rational integrated pest management strategies for L. botrana. Due to the laboratory results presented on parasitoid emergence, even though field bioassays would give a more exhaustive evaluation, it appears kaolin can be compatible with T. cacoeciae in L. botrana management. [ABSTRACT FROM AUTHOR]

Ecological gradients are important for species in nature. However, there is a need to better understand how varying levels of disturbance influence the functional roles of beetle species within a crop area characterized by different types of natural vegetation. Here, we test such effects by studying a perturbation gradient – an ecological gradient that transitions from a natural area near the ecotone of a deciduous forest (a transitional zone between crops and forest) to a crop. The beetle specimens were collected along transects parallel to the ecotone, and their functional diversity was assessed using a clustering analysis and functional indices. We identified 21 species of beetles, and the highest species richness was observed in the Chrysomelidae family. A functional analysis revealed two main groups, including primary consumers (phytophages) and entomophagous beetles. The hedge area exhibited functional richness similar to the natural area. However, the functional evenness was consistently low across all the areas. The presence of natural habitats positively influenced beetle functionality and potentially impacted the abundance of deleterious species of beetles and their establishment at a low spatial scale. These findings underscore the importance of considering different spatial-scale-dynamics in agroecosystems and highlight the potential role of natural habitats in fostering functionality to indirectly control pests. [ABSTRACT FROM AUTHOR]

We analyze the percolation threshold of square lattices comprising a combination of sites with regular and extended neighborhoods. We found that the percolation threshold of these composed systems smoothly decreases with the fraction of sites with extended neighbors. This behavior can be well-fitted by a Tsallis q-Exponential function. We found a relation between the fitting parameters and the differences in the gyration radius among neighborhoods. We also compared the percolation threshold with the critical susceptibility of nearest and next-to-nearest neighbor monoculture plantations vulnerable to the spread of phytopathogen. Notably, the critical susceptibility in monoculture plantations can be described as a linear combination of two composite systems. These results allow the refinement of mathematical models of phytopathogen propagation in agroecology. In turn, this improvement facilitates the implementation of more efficient computational simulations of agricultural epidemiology that are instrumental in testing and formulating control strategies.

The chemical study of Sechium mexicanum roots led to the isolation of the two new saponins {3-O-beta-D-glucopyranosyl (1 --> 3)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranoside} (1) and {3-O-beta-D-glucopyranosyl (1 --> 3)-beta-D-glucopyranosyl-2beta,3beta,16alpha,23-tetrahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-[beta-D-apiosyl-(1 --> 3)]-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranoside} (2), together with the known compounds {3-O-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl-2beta,3beta,6beta,16alpha,23-pentahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranoside} (3), tacacosides A(1) (4) and B(3) (5). The structures of saponins 1 and 2 were elucidated using a combination of (1)H and (13)C 1D-NMR, COSY, TOCSY, gHMBC and gHSQC 2D-NMR, and FABMS of the natural compounds and their peracetylated derivates, as well as by chemical degradation. Compounds 1-3 are the first examples of saponins containing polygalacic and 16-hydroxyprotobasic acids found in the genus Sechium, while 4 and 5, which had been characterized partially by NMR, are now characterized in detail., (2009 John Wiley & Sons, Ltd.)