Insects

Bradysia difformis is a notorious pest in mushroom production in China. Biological control using Bacillus thuringiensis (Bt) offers an environmentally friendly and effective strategy against this pest. Here, we show that the complete genome of strain JW-1 consists of one circular chromosome and seven circular plasmids. JW-1-Plasmid 4 comprises 127,921 bp with a GC content of 33.9%, and is predicted to contain 131 genes, including six insecticidal genes: cry4Aa, cry4Ba, cry10Ab, cry11Aa, cyt1Aa, and cyt2Ba. A 3542-bp fragment containing the cry4Aa gene was amplified from this strain. Phylogenetic analysis based on Cry4 toxin sequences showed that JW-1 Cry4 toxin belongs to the Cry4Aa toxin cluster. A Cry4Aa fusion protein was subsequently expressed in E. coli and purified using Ni-IDA affinity chromatography. A larval feeding assay showed that purified Cry4Aa was toxic to B. difformis larvae, with an LC₅₀ of 2.71 ng/mL. These results confirmed the identity and bioactivity of Cry4Aa from strain JW-1, offering a promising biological control agent against this major pest.

Lagria nigricollis (Coleoptera: Tenebrionidae) is a forest pest, widely distributed in East Asia. The impact of climate change on its distribution is currently unknown. To better understand how the geographic distribution of this species responds to future climate change, this study employed the MaxEnt model, integrating 21 environmental variables, to explore changes in its distribution range under different climate scenarios. The results indicated that the average area under the receiver operating characteristic curve (AUC) of the MaxEnt model across different periods is 0.991, demonstrating the reliability of the model’s predictions. The precipitation of the warmest quarter (bio18) and the temperature seasonality (bio04) were the most important environmental variables. Under current conditions, the suitable areas for L. nigricollis are mainly located in China (North China and Central China), the Korean Peninsula, and Japan (Kyushu, Shikoku, and the southern part of Honshu). In the 2050s and 2070s, suitable areas are expected to expand under three socioeconomic pathways, which are 1.08–1.33 times larger than they are currently. The expanded areas are mainly located in the northern part of the current suitable regions. The centroids of suitable areas will shift northward under future climate conditions. To limit the northward expansion of this species, primary control regions will focus on China (the junction of Inner Mongolia–Xinjiang and Northern China), Russia (the southeastern part of the Far Eastern Federal District), and Japan (Hokkaido). The results of this study provide a scientific basis for the forest pest control and distribution prediction of Lagria nigricollis.

An effective surveillance method for invasive insect pests is critical for timely detection and management. This study explores the effectiveness of eight active sampling methods for detecting the presence of the two-spot cotton leafhopper (Amrasca biguttula (Ishida) (Hemiptera: Cicadellidae)), a newly emerging adventive pest in the U.S.A. that is causing economic losses in cotton and okra. We conducted field studies to compare aspirating, bagging, beat sheet, sweep netting, and four tray-based methods: a dry tray, or a tray with 70% isopropyl alcohol, tap water, or soapy water. While aspirating and bagging served as adequate sampling methods, we found that sampling with a tray containing 70% isopropyl alcohol proved to be the most effective and time-efficient approach. This method consistently enabled rapid detection of adult male specimens across both low- and high-population field sites, facilitating reliable morphological identification.