Control of Leaf-footed Bug Leptoglossus zonatus and Shield-backed Bug Pachycoris klugii with Entomopathogenic Fungi

The pathogenicity of three isolates of Beauveria bassiana (Bals.) Vuil. and one isolate of Metarhizium anisopliae (Metsch.) Sorok. (Deuteromycotina: Hyphomycetes) was assessed in the laboratory against adults of the leaf-footed bug Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae) and the shield-backed bug Pachycoris klugii Burmeister (Heteroptera: Scutelleridae), the two most frequent pest species in physic nut ( Jatropha curcas L., Euphorbiaceae) plantations in Nicaragua. In a dipping bioassay, the median lethal concentration (LC) of the most efficient strain, M. anisopliae NB, was determined as 4.34 106 50 conidia/ml for adult P. klugii . In a field trial, a scheduled high-volume spray regime using B. bassiana increased fruit yield by 28%, and was more effective than malathion or an aqueous extract of ground neem seeds. The effectiveness of M. anisopliae was further tested in field cages covering entire trees and containing a predetermined number of insects. Mineral oilbased ultra-low volume controlled droplet applications of M. anisopliae at a rate of 1 1010 conidia/tree were made using hand-held Micron ULVA + sprayers. The corrected mortalities ranged from 65% in P. klugii to 94% in L. zonatus.     

Life table for Leptoglossus occidentalis Heidemann (Heteroptera: Coreidae) and prediction of damage in lodgepole pine seed orchards

Abstract 1 Fecundity, egg hatch and nymphal survivorship of Leptoglossus occidentalis Heidemann were determined and used to develop a damage prediction formula for seed bugs in lodgepole pine seed orchards. 2 A single overwintered L. occidentalis female may lay up to 80 eggs during early and mid‐season cone development. 3 Up to 83.4% of eggs that were attached to branches with tape hatched successfully, compared with 53.5% of eggs attached to needles with wire. Egg parasitism was only observed in egg masses attached with wire. 4 Egg masses attached with wire suffered approximately 30% mortality from parasitism, primarily by Gryon pennsylvanicum (Ashmead). 5 Approximately 15.1 and 2.5% of first instars survived to adulthood in 2000 and 2001, respectively. Survival of caged nymphs that were protected from predators was 14.5 and 17.8%, respectively. 6 A composite survival table indicated that 9.3% of eggs laid by L. occidentalis are expected to survive to adulthood. 7 Based on previously determined damage estimates for each life stage of feeding during three periods of cone development, a hypothetical density of one seed bug per tree early in the season will result in an expected seed loss of approximately 310 seeds.     

Evaluation of damage to physic nut (Jatropha curcas) by true bugs

The type of injury and amount of damage to the fruits and seeds of physic nut (Jatropha curcas L., Euphorbiaceae) caused by two species of fruit feeding true bugs, Pachycoris klugii Burmeister (Heteroptera: Scutelleridae) and Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae), and the flower feeding true bug, Hypselonotus intermedius Distant (Heteroptera: Coreidae), were assessed using field cages. The parameters analysed were infructescence, fruit, seed and seed kernel weight, seed length, fruit and seed abortion, seed malformation and oil and protein content of the seed kernels. All three species reduced overall yield. The two members of the fruit feeding guild led to premature fruit abortion and malformed seeds. Reduction of fruit, seed and seed kernel weight as well as seed length could be expressed as linear regressions of adult population densities. The oil content of the seeds was slightly reduced by the bugs, but protein content remained unchanged. Damage increased with the developmental stage of the larvae. Whereas adult L. zonatus of both sexes produced more damage than the nymphs, female P. klugii caused less damage than nymphs, and male P. klugii no significant damage at all. H. intermedius is a pollinator of this entomogamous plant. At high densities, however, it reduced the number of fruits maturing.     

Micro X‐ray computed tomography suggests cooperative feeding among adult invasive bugs Leptoglossus occidentalis on mature seeds of stone pine Pinus pinea

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我国入侵害虫西部喙缘蝽的溯源分析

本文对我国外来入侵物种西部喙缘蝽Leptoglossus occidentalis Heidemann, 1910进行了溯源分析,依据对国内种群的观察和标本简要描述了其形态特征和生活习性。通过野外采集国内种群标本,提取扩增COI基因序列,结合原产地和国外其他入侵种群的公共序列,构建西部喙缘蝽COI基因数据集,以中国入境口岸对木材的检疫情况为参考,分析西部喙缘蝽的入侵来源。全世界目前已知10种单倍型,中国存在4种。山东青岛种群有H_8、H_9和H_10三种单倍型,其中H_8与韩国共享,H_9和H_10为中国特有单倍型,青岛种群可能部分来自韩国;山东烟台两个采集点的种群都属于H_2,可能来自北美东部,与青岛种群的入侵来源不同。以上分析表明,我国西部喙缘蝽种群可能来源于多次独立入侵事件,同时在国内发生了小范围的扩散迁移。本研究首次对我国入侵害虫西部喙缘蝽做了溯源分析,为更好地制定规制措施,开展检疫防治工作提供了科学依据。     

Responses of native egg parasitoids to the invasive seed bug Leptoglossus occidentalis

1. The Western conifer seed bug Leptoglossus occidentalis, a native insect of North America, was accidentally introduced in Europe in the late 1990s. Since then, it has spread rapidly. Biological control could provide an efficient management option but natural enemies of the pest have been poorly examined in Europe.
2. In this study, we exposed sentinel egg masses and collected naturally laid egg masses in southern France in 2016 and 2017, to identify the egg parasitoids of L. occidentalis and investigate their potentials.
3. Three egg parasitoids were detected: Anastatus bifasciatus, Ooencyrtus pityocampae and Ooencyrtus telenomicida. The overall parasitism was low compared to that observed in the native range with 6.4% of all eggs being parasitized, while 17.1% of egg masses carried at least one parasitized egg. The total number of parasitized egg masses was similar between parasitoid species, but the mean number of parasitized eggs per egg mass was highest for A. bifasciatus (5.57 vs. 1.25 for Ooencyrtus spp.).
4. Sentinel egg masses underestimated the parasitism compared to natural egg masses (respectively, 1.42% and 7.71%).
5. Our results suggested that the three generalist parasitoids detected can respond in a Leptoglossus egg density-dependent manner, but this requires further investigations.

     

Functional morphology of the hind legs as weapons for male contests inLeptoglossus australis (Heteroptera: Coreidae)

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