Pheromone antagonism in Plu tella xylostella (Linnaeus) by sex pheromones of two sympatric noctuid moths.

BACKGROUND: Responses to sex pheromones are commonly antagonized by pheromone components of closely related species. Pheromone antagonism has not been widely explored for phylogenetically distant species that have completely different pheromone components. Yet, pheromone components of sympatrically occurring species may also interfere with each other even if these species are distantly related. Here, the effects of heterospecific pheromones on electrophysiology (electroantennogram, EAG) and behavioral responses were tested on the diamondback moth Plutella xyloslella (Plutellidae) and two sympatric noctuid moth species, Spodoptera litura and Spodoptera exigua, whose larvae also feed on Brassica crops. RESULTS: The sex pheromone blend of P. xyloslella, and its components, did not elicit EAG responses in males of the two noctuid species, while sex pheromone components of the noctuid moths elicited significant EAG responses in P. xyloslella males. In wind tunnel bioassays, both (Z, E)-9, 12-tetradecadienyl acetate (ZE-9,12-14:OAc) and (Z, E)-9, 11-tetradecadienyl acetate (ZE-9,11-14:OAc), sex pheromone components from the noctuid moths, inhibited the upwind flight behavior of P. xyloslella males toward an intraspecific pheromone odor source. In Brassica fields, sex pheromone lures of P. xyloslella did not influence trap catches of the noctuid moths, while P. xyloslella pheromone lures baited with either ZE-9,11-14:OAc or ZE-9,12-14:OAc decreased trap catches of P. xyloslella males in a dose-dependent manner. Trap catches of P. xylostella males were also affected by the proximity of ZE-9,11-14:OAc or ZE-9,12-14:OAc to P. xylostella lures. CONCLUSION: The uni-directional pheromone antagonism by ZE-9,11-14:OAc and ZE-9,12-14:OAc suggests innovative semiochemical-based strategies for the management of P. xyloslella and other economically important pests in Brassica fields. © 2021 Society of Chemical Industry.

Contribution to the knowledge of Dialeurodes (Gigaleurodes) Quaintance amp; Baker (Hemiptera: Aleyrodidae), with description of a new species from China.

A new whitefly species, Dialeurodes (Gigaleurodes) parakmeriae Wang sp. nov., collected on Parakmeria sp. (Magnoliales: Magnoliaceae) in Shuangxikou (Zhejiang, China) is described using morphology, line illustrations, photographs and scanning electron microscope (SEM) images. In addition, Dialeurodes (Gigaleurodes) maxima Quaintance Baker, is reported as new to the fauna of China. An identification key to Chinese Dialeurodes (Gigaleurodes) species is provided. The holotype is deposited in the Insect Collection of Zhejiang Agriculture Forestry University (ZAFU).

Description of a new species of Aleuroclava Singh, 1931 (Hemiptera, Aleyrodidae) infesting Schima superba from China.

A new whitefly species, Aleuroclava schimae Wang, sp. nov. infesting leaves of Schima superba (Parietales, Theaceae) is described and illustrated from Zhejiang, China. Puparia of the new species are elliptical, broad at the transverse molting suture region and broadly truncate posteriorly. Thoracic and caudal tracheal pores are discernible. In life, the puparia are covered by a thin layer of white wax.

Host plants alter their volatiles to help a solitary egg parasitoid distinguish habitats with parasitized hosts from those without.

When attacked by herbivores, plants emit volatiles to attract parasitoids and predators of herbivores. However, our understanding of the effect of plant volatiles on the subsequent behaviour of conspecific parasitoids when herbivores on plants are parasitized is limited. In this study, rice plants were infested with gravid females of the brown planthopper (BPH) Nilaparvata lugens for 24 hr followed by another 24 hr in which the BPH eggs on plants were permitted to be parasitized by their egg parasitoid, Anagrus nilaparvatae; volatiles from rice plants that underwent such treatment were less attractive to subsequent conspecific parasitoids compared to the volatiles from plants infested with gravid BPH females alone. Chemical analysis revealed that levels of JA and JA-Ile as well as of four volatile compounds-linalool, MeSA, α-zingiberene and an unknown compound-from plants infested with BPH and parasitized by wasps were significantly higher than levels of these compounds from BPH-infested plants. Laboratory and field bioassays revealed that one of the four increased chemicals-α-zingiberene-reduced the plant's attractiveness to the parasitoid. These results suggest that host plants can fine-tune their volatiles to help egg parasitoids distinguish host habitats with parasitized hosts from those without.

Effect of larvae treated with mixed biopesticide Bacillus thuringiensis-abamectin on sex pheromone communication system in cotton bollworm, Helicoverpa armigera.

Third instar larvae of the cotton bollworm (Helicoverpa armigera) were reared with artificial diet containing a Bacillus thuringiensis-abamectin (BtA) biopesticide mixture that resulted in 20% mortality (LD20). The adult male survivors from larvae treated with BtA exhibited a higher percentage of "orientation" than control males but lower percentages of "approaching" and "landing" in wind tunnel bioassays. Adult female survivors from larvae treated with BtA produced higher sex pheromone titers and displayed a lower calling percentage than control females. The ratio of Z-11-hexadecenal (Z11-16:Ald) and Z-9-hexadecenal (Z9-16:Ald) in BtA-treated females changed and coefficients of variation (CV) of Z11-16:Ald and Z9-16:Ald were expanded compared to control females. The peak circadian calling time of BtA-treated females occurred later than that of control females. In mating choice experiment, both control males and BtA-treated males preferred to mate with control females and a portion of the Bt-A treated males did not mate whereas all control males did. Our Data support that treatment of larvae with BtA had an effect on the sex pheromone communication system in surviving H. armigera moths that may contribute to assortative mating.

[Treatment of displaced humeral supracondylar fractures in children with external fixation using plaster or splint].

OBJECTIVE: To investigate the therapeutic effects of closed reduction and external fixation (plaster or splint) for the treatment of displaced humeral supracondylar fractures in children. METHODS: From March 2007 to September 2009,33 children (15 female and 18 male) with humeral supracondylar fractures treated in our hospital, ranging from 3 to 12 years old with an average of 6.4 years old. All the fractures were extension-type injuries, the flexion injures were excluded in our study. The humeral supracondylar fractures were classified according to Gartland classification. There were 21 Type H and 12 type III. In the initial treatment, all the patients were treated with closed reduction and external immobilization. The blood supply of the damaged upper extremity was evaluated before and after treatment. Clinical assessment was obtained at final follow-up using Flynn criteria, and radiologic assessment was obtained using Baumann and lateral humerocapitellar angles. RESULTS: All the children were treated successfully with closed reduction in the initial time; 24 children maintained limb alignment by external immobilization. Nine patients lost position due to the swelling around the elbow which affected unstable external fixation during the follow-up, 5 of which were treated with a repeated closed reduction and internal fixation with Kirschner wires, 4 of which were treated with traction. Thirty-one patients had a satisfactory outcome and 2 patients had an unsatisfactory outcome according to the Flynn criteria at the latest follows-up. CONCLUSION: Closed reduction and external stabilization is an important method for the treatment of displaced humeral supracondylar fractures in children. Making regular follow-up visits after closed reduction and casting is important for patients to maintain acceptable alignment, avoid complications and diagnose any loss of reduction.