蝗虫的发生与防控

蝗虫暴发引起的灾害是全球重要的生物灾害,可影响到全世界十分之一的人口。自2019年,东部非洲、西亚、南亚多个国家遭遇严重的沙漠蝗虫灾害,这场蝗灾不但对该区域的粮食安全构成严重威胁,而且还有可能引发严重的人道主义危机。为了制定合理的防治方案,实施有效防控,避免大规模蝗灾的发生,需要掌握蝗虫的生物学、生态学、暴发和为害规律、防治策略和技术特点及其进展等。本文介绍了世界各地包括沙漠蝗、飞蝗、澳大利亚疫蝗在内的11种可以引起灾害的重要种类的主要分布、为害和特性,并对国内外蝗虫防治策略、技术进展进行了重点综述。最后,针对目前蝗虫防治存在的问题提出了相应建议。     

Mass windborne migrations extend the range of the migratory locust in East China

1. Migratory insect pests pose a substantial challenge to global food security. These issues are particularly acute when pest incursions occur considerably beyond the expected range, through natural migration or human‐aided transport, because the lack of species‐specific control strategies and a potential absence of species‐specific natural enemies in the newly‐invaded area may lead to rapid establishment of a new pest.
2. One such threat is posed by the Oriental migratory locust Locusta migratoria manilensis in China, which, historically, has been restricted to eastern China from the Bohai Gulf southwards, and now threatens to expand its range into the agriculturally important region of northeast China.
3. We analyzed data from a recent outbreak of migratory locusts in Heilongjiang Province (extreme northeast China), > 700 km north of its current known range, and identified the source region, timing of arrival and probable migratory routes of this incursion.
4. We further show that warming temperatures in this region will likely allow subsequent invasions to establish permanent populations in northeast China, and thus authorities in this important crop‐producing region of East Asia should be vigilant to the threat posed by this species.

     

Biological performance of Diclidophlebia smithi (Hemiptera: Psyllidae), a potential biocontrol agent for the invasive weed Miconia calvescens

Diclidophlebia smithi Burckhardt, Morais and Picanço (Hemiptera: Psyllidae) is a promising biological control agent of Miconia calvescens DC. (Melastomataceae), a neotropical invasive weed in forest ecosystems in French Polynesia and Hawaii and a threat in Australia, where it was also introduced. A study on the reproductive performance of D. smithi under laboratory conditions through life expectancy and fertility tables is presented. Results indicated that this psyllid has a high reproductive capacity (R ₀>1 and r _m >0) and a short life cycle (46–47 days) and can have up to nine generations per year. The critical period of its life cycle is during the nymphal stage which is clearly inadequate for field introductions. The best age for introducing D. smithi against M. calvescens is the 4th day of the adult stage. D. smithi is easily mass-reared and has a short life cycle and a high reproductive capacity, which are desirable characteristics for a biological control agent.     

Stand edge effects on distribution and condition of Diprionid sawflies

1 We investigated stand edge effects on Diprion pini cocoon condition and distribution after an outbreak of unprecedented magnitude in Finland. We hypothesized that forest fragmentation and the resulting proportional increase in stand edge habitats may have led to the increase in outbreak area: D. pini may profit from edge habitats and so escape its control mechanisms more easily. This hypothesis was based on the observation that no outbreak occurred in neighbouring Russian Karelia, where the proportion of edge habitats between different stand types and/or successional stages is significantly less than in Finland. 2 To test the hypothesis, we determined the amount and condition of cocoons in an outbreak area, along transects going from stand centres through edge habitats, towards neighbouring stand centres. 3 Both the total number and number of cocoons in different conditions varied significantly between edges and centres. The effects were more pronounced when age difference between neighbouring stands increased. 4 Edge habitats did not benefit D. pini. Both the total number and number of hatched cocoons were consistently higher in centre than in edge habitats. 5 Defoliation was unrelated to distance from the edge, even on transects where cocoon density and condition was correlated to distance from the edge. 6 We conclude that edge habitats have an inhibitive effect on D. pini densities, and therefore our original hypothesis was rejected. The importance of small mammals to D. pini mortality was demonstrated, and we suggest further investigation of this predator–prey relationship because of its potential for limiting outbreak risk and/or damage through silvicultural measures.     

Comparative proteomic analysis between fifth‐instar nymphs and adults of Asian citrus psyllid Diaphorina citri

Asian citrus psyllid Diaphorina citri Kuwayama is extremely problematic worldwide, particularly where Huanglongbing (HLB) disease, the most serious and devastating of citrus diseases, is found. The threat is a result of its ability to transmit the causal agent of HLB, Candidatus Liberibacter asiaticus (CLas) bacterium. Improvements in proteomics, mass spectrometry, bioinformatics tools and gene ontology annotation facilitate the mapping and large‐scale identification and quantification of proteins. To date, only a few comparative proteomic studies report the developmental proteomic changes of hemimetabolous and plant–disease vector insects. Two‐dimensional gel electrophoresis analysis of D. citri total protein is able to detect qualitative and quantitative developmental differences. Liquid chromatography‐tandem mass spectrometry identifies 89 protein spots. Most proteins are metabolism and bioenergetics‐related. Nineteen protein spots are found to be implicated in stress/defence/immunity; 7 in development regulation; 9 in nervous system functions; 4 in the reproductive system; 23 in cytoskeleton and muscle organization; and 4 in movement, flight and other processes. Significant increases in the level of proteins related to structural constitution of the skeleton, stress/defence/immunity, reproduction system, muscles, locomotion and flight are found in adults, consistent with the fact that D. citri is a hemimetabolous insect, whereas proteins involved in developmental regulation are higher in the nymphal stage. The identification of these variably expressed proteins between the nymph and adult stages, linked with the basis of their physiological roles, will lead to a better understanding of the factors influencing development in D. citri and the regulation of some crucial metabolic pathways. It may also help to identify targets for genetic manipulation using RNA interference or other techniques to disrupt Asian citrus psyllid development, lifespan or its ability to transmit CLas.     

Consequences of defoliation on phenological interaction between Epirrita autumnata and its host plant, Mountain Birch

1. Defoliation-induced changes in the budbreak phenology of Mountain Birches ( Betula pubescens ssp. tortuosa (Ledeb.) Nyman), and their effects on herbivore performance, were investigated during an outbreak of the spring-feeding geometrid, Epirrita autumnata (Bkh.).
2. Total defoliation (followed by refoliation) by E. autumnata larvae was required to achieve significant delaying of budbreak of Mountain Birch one year after damage.
3. Delayed budbreak has potentially deleterious effects on herbivore performance. However, E. autumnata larvae show phenotypic responses that increase the synchrony between larvae and leaves: high larval density, a prerequisite for severe defoliation, delays egg hatch in the following year.
4. Late hatching larvae performed as well on birches with delayed budbreak due to the previous year's total defoliation as did early hatching larvae on birches with earlier budbreak.