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Abstract:The Pear Psyllid, Cacopsylla bidens (Šulc, 1907), is here reported from the Department of Canelones, the major region of pear production in Uruguay. Previous records of C. pyricola (Foerster, 1848) from Uruguay are misidentifications of C. bidens. Information is provided on the taxonomy and biology of this species.

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While chemical control is still the primary strategy for insect pest management in fruit production, alternative strategies such as biological control need to be incorporated. Biological control may benefit from the behavioral manipulation of natural enemies using volatile organic compounds (VOCs). Among these, herbivore-induced plant volatiles (HIPVs) provide potential tools for attracting or retaining predators and parasitoids of insect pests. In southern South America, the pear psylla Cacopsylla bidens (Hemiptera: Psyllidae) has become a major pest in pear orchards. In this study, we identified VOCs emitted by pear plants in response to attack by C. bidens and compared these with VOCs induced by a leaf-chewing insect, Argyrotaenia sphaleropa (Lepidoptera: Tortricidae). Moreover, we evaluated the behavioral response of Chrysoperla externa (Neuroptera: Chrysopidae) to HIPVs from pear plants damaged by either herbivore. Plants damaged by the pear psylla emitted VOC blends with increased amounts of aliphatic aldehydes. In contrast, leafroller damage resulted in increased amounts of benzeneacetonitrile, (E)-4,8-dimethylnona-1,3,7-triene, ꞵ-ocimene and caryophyllene. In olfactometer bioassays, larvae of C. externa were attracted to herbivore-damaged plants when contrasted with undamaged plants. When plant odors from psylla-damaged were contrasted with those of leafroller-damaged plants, C. externa larvae preferred the former, also showing shorter response lag-times and higher response rates when psylla-damaged plants were present. Our results suggest that psylla-induced aliphatic aldehydes may be used as prey-specific chemical cues by chrysopid larvae. Our findings contributes to the general notion of using semiochemicals as tools for attracting and retaining natural enemies in agroecosystems.

Argyrotaenia sphaleropa is a lepidopteran pest in deciduous fruit orchards in Uruguay. The primary control method of these pests is the use of chemical insecticides; however, alternative strategies, friendlier to the environment and compatible with a regional programme of integrated pest management, are definitely needed. Biological control with the use of local entomopathogenic microorganisms could be a sustainable solution. In this study, a biological screening was conducted to characterize spore‐forming bacilli for their capacity to kill larvae of this species. Bacillus thuringiensis, B. pumilus, B. aryabhattai, B. amyloliquefaciens and Lysinibacillus xylanilyticus were identified based on sequence analyses of 16S and partial GyrB gene. Lysinibacilus xylanilyticus showed the highest mortality towards first‐instar larvae fed with diet treated with spore suspensions. Specific virulence factors like proteinaceous parasporal inclusions were observed not only in isolates of B. thuringiensis but also in L. xylanilyticus. Ordering of isolates based on multivariate analysis of putative secondary virulence factors like biosurfactant and biofilm production, haemolytic activity and motility, separated the virulent isolate of L. xylanilyticus. This is the first report of L. xylanilyticus causing mortality in A. sphaleropa or any other member of Lepidoptera. A search for more virulent strains of this species is envisaged.