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Diglyphus wani (Hymenoptera: Eulophidae) is a dominant parasitoid that attacks agromyzid leafminers. Two reproductive types occur in D. wani: arrhenotoky (in which virgin females produce only male offspring; and virgin females mate with males to produce bisexual offspring) and thelytoky (in which virgin females produce female offspring). As a potential biological control agent, exploring the differences in the relevant biological parameters of both strains is necessary. In this study, comparisons between the two strains of D. wani were performed by evaluating the life table and host-killing rate. The thelytokous strain exhibited significantly better life table parameters than its arrhenotokous counterpart. Higher values for the intrinsic rate of increase, finite rate of increase, net reproductive rate, and fecundity were found in the thelytokous strain. The thelytokous strain also performed better than the arrhenotokous strain in terms of net parasitism, host-feeding, host-stinging, and total host-killing rates. Thus, populations of the thelytokous strain could grow fast and kill more hosts. In conclusion, the thelytokous strain of D. wani may be the more promising biological agent against agromyzid leafminers compared to its arrhenotokous counterpart. Also, since the thelytokous strain of D. wani is only known to produce females, it should be given priority in future biocontrol applications owing to the cost savings of breeding only females.

Temperature, as a critical abiotic factor, might influence the effectiveness of biological control by parasitoids in host-parasitoid systems. In this study, Neochrysocharis formosa (Westwood), a larval endoparasitoid, is used to investigate the efficacy of biological control on a vegetable agriculture pest, Liriomyza sativae Blanchard, reared on kidney bean (Phaseolus vulgaris L.), at four constant temperatures (26, 29, 32, and 35°C) under laboratory conditions. Our results show that high temperatures (29, 32, and 35°C) do not significantly affect lifetime host-killing events of female adults by increased daily host-killing events compared to temperature of 26°C, although their lifespans decrease with an increase in temperatures. Each life-history trait of female adults (lifespan, parasitism, stinging, or non-reproductive host-killing events) present a linear relation with temperatures and host-feeding events, respectively. Our findings contribute to a better understanding of biocontrol efficacy of parasitoid N. formosa against agromyzid leafminers at high-temperature seasons or environments.

Diglyphus species are ecologically and economically important on agromyzid leafminers. In 2018, a thelytokous species, Diglyphus wani Liu, Zhu & Yefremova, was firstly reported and described. Subsequently, the arrhenotokous D. wani were discovered in Yunnan and Guizhou Provinces of China. We compared the morphological characteristics of thelytokous and arrhenotokous strains. However, the females of two strains had a strongly similar morphology and showed subtle differences in fore- and hind-wings. The difference was that forewing of arrhenotokous female was with denser setae overall, showing that costal cell with 2 ~ 4 rows of setae on dorsal surface and the setae of basal cell with 15 ~ 21 hairs and forewing of thelytokous female was with two rows of setae on dorsal surface and basal cell with 10 ~ 15 hairs generally. The setation beneath the marginal vein of the hind-wing of arrhenotokous female is denser than the same area of thelytokous female. To explore the genetic divergence between thelytokous and arrhenotokous strains of D. wani, the mitochondrial and nuclear gene were applied and sequenced. The polygenic analyses revealed that two strains can be distinguished by COI, ITS1 and ITS2. The mean sequence divergence between the two strains was 0.052, 0.010 and 0.007, respectively. Nevertheless, the 28S gene was unfeasible due to its containing a sharing haplotype between different strains. The two strains of D. wani are dominant parasitoids against agromyzid leafminers and such effective discernible foundation provides future in-depth studies on biological characteristics, along with insight into field application of two strains of D. wani.

Placing a swirl nozzle composed of a yam channel and an air-jet nozzle in a traditional ring spinning frame can reduce yam hairiness. In this study, two types of swirl nozzles, namely, the circular swirl nozzle and the elliptical swirl nozzle, are designed to optimize the inside structure of the swirl nozzle and improve the yam quality. Yam performance is evaluated based on the hairiness, breaking strength, and evenness of the yam. Experimental results show that the two types of swirl nozzles have effective effects on the ring yam qualities compared with the traditional method. The mechanisms of the said effects can be explained via yam de-twisting and re-twisting under the vortex action in the yam channel. Yarn channels have different effects on yam properties because of their different airflow patterns. The circular swirl nozzle is found to produce better yam properties, including S3 value (the total number of hairiness equal to or exceeding 3 mm per 10 m), breaking strength, and evenness than the elliptical swirl nozzle under similar processing parameters. [ABSTRACT FROM AUTHOR]