Soil sampling for <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> spores in Queensland sugarcane fields

Three sugarcane fields in Bundaberg and four fields in each of the Burdekin, Tully and Innisfail (Queensland, Australia) were sampled for spores of Metarhizium anisopliae (Metchnikoff) (Deuteromycotina: Hyphomycetes). This entomopathogenic fungus is the active ingredient in the biocide “BioCane^TM”, which was developed for the management of the greyback canegrub Dermolepida albohirtum (Waterhosue) (Coleoptera: Scarabaeidae) and other scarabs in cane fields. Fields sampled were of different crop ages and all had a history of BioCane^TM treatment in Plant Cane in past years. Soil samples were taken in each field from four depths (0–10, 10–20, 20–30 and 30–40 cm below soil level) with the use of an auger. Spore levels were highest at the depths of 10–20 and 20–30 cm. Spore levels differed between locations with Innisfail and Tully recording the highest spore counts. Spores were also found in the inter-row space in plots sampled in Tully. Sampling statistics were determined for M. anisopliae spores at the four soil depths with 0.1 and 0.25 precision levels. Three sampling methods were compared (use of marker beads; use of 100 mm auger and 150 mm auger). Samples that relied on marker beads resulted in higher spore counts, however, an auger can still be used since BioCane^TM does not normally contain coloured markers. Results obtained demonstrate the ability of the pathogen to translocate in soil profile and across rows, most likely due to grub movements and other soil fauna. Sampling for M. anisopliae spores provides good monitoring of their levels in soil. The implications of this on grub management decisions are discussed.     

花生蛴螬空间分布型研究及药效评价方法探讨

花生蛴螬田间分布属于聚集分布。在已知的m m回归关系的基础上提出了不同密度下花生蛴螬的理论抽样数和防治花生蛴螬的田间试验方法 ,并对 2种药效计算方法进行了评价。     

Immunological responses of rabbits artificially infested with the cattle grubs Hypoderma bovis (L.) and H. Lineatum (De Vill.) (Diptera: Oestridae)

Boulard Chantal and Weintraub J. 1973. Immunological responses of rabbits artificially infested with the cattle grubs Hypoderma bovis (L.) and H. lineatum (De Vill.) (Diptera : Oestridae). International Journal for Parasitology3: 379–386. Immunological responses against first-instar larvae of Hypoderma bovis (L.) and H. lineatum (De Vill.) were traced in artificially infested rabbits in which larvae grew normally in the first instar but did not survive to the second instar. Passive haemagglutination demonstrated a rapid rise in antibody titres during the first 2 months to maximum levels that persisted until about 200 days of the infestation. Immunoelectrophoretic analyses of the sera demonstrated that larval metabolic products were more important than breakdown products of dead larvae in stimulating the production of antibodies. Larval collagenase, which seemed to induce the most significant immune response, was inhibited by homologous antibodies in the serum of a hyperimmunized rabbit. The implications of these results for infestations in the normal bovine host were discussed, with emphasis on the need to identify antigenic fractions other than collagenase, which by itself had not produced total control of larvae in previous vaccination tests.     

The effect of root damage caused by simulated white grub attack on the growth,yield and water-use of groundnut plants

White grubs (larval scarabaeids) are now recognized as being important pests of groundnut (peanut) in many parts of the world because of their ability to damage roots. A method of simulating white grub damage to groundnut plants was developed to obtain an indication of how the feeding activity of these insects influences plant growth. The effect of root cutting and drought stress on water uptake and biomass production was evaluated, with roots being cut at three depths in the late vegetative and early podfilling stages. As groundnut plants are often grown under conditions of drought stress, the effects of which would be accentuated by root damage, this factor was introduced into the experiment. Plant water-use measurements indicated that the root systems of plants cut 30 days after emergence (DAE) and watered twice a week became fully functional again after 40 days. Pod and total biomass production were however significantly less than those of the uncut control plants, with drought stress reducing yields below the well-watered controls, particularly when cut at 10 cm below the soil surface. The root systems of plants cut 51 DAE did not regrow to any appreciable extent, and rates of plant water-use remained less than half of the uncut control plants. Over all treatments, there was a strong positive correlation between total (and pod) biomass and plant water-use. It was concluded that the phenological stage of the plant at which root damage occurred had a profound influence on the subsequent recovery in root growth and function, and ultimately on pod yield.     

Arthropod abundance in tall fescue,Lolium arundinaceum,pastures containing novel ‘safe’ endophytes

Poor livestock performance on tall fescue is linked to infection by a fungal endophyte that enhances grass resistance to stress, including herbivory, while producing ergot alkaloids toxic to vertebrate grazers. Novel ‘safe’ endophyte/grass associations produce no ergot alkaloids yet retain stand persistence, but they could be more susceptible to insect outbreaks. We tested the hypothesis that grass‐feeding insects are more abundant in novel endophyte pastures compared with those containing common endophyte. Above‐ and below‐ground herbivores were sampled across two growing seasons in pastures containing common strain endophyte (KY31), novel endophytes (MaxQ or AR584) or endophyte free. We also sampled natural enemies as an indicator of possible tritrophic effects. With a few exceptions, numbers of predatory, chewing (grasshoppers, crickets, caterpillars) or sucking insects (leafhoppers, planthoppers) were similar in common and novel endophyte pastures. Contrary to our hypothesis, Aphrodes spp. leafhoppers were more abundant in KY31 than other pasture types in 2008; their nymphs also were more abundant in KY31 than in MaxQ in 2009. Adults (but not total numbers or nymphs) of another leafhopper, Psammotettix striatus, were less abundant in KY31 than other pasture types in 2009. Popillia japonica and Cyclocephala spp. grubs did not differ in density, weight or instar among the endophyte‐containing associations. In feeding assays, armyworm (Mythimna unipuncta) survival was higher on MaxQ and NE9301, and weight gain was higher on NE9301, suggesting armyworm outbreaks could be more severe on such grasses, but that result may not be attributable solely to alkaloids because common strain and endophyte‐free grasses did not differ in either parameter. Caterpillar abundance did not differ among pasture types in the field. Our results suggest that re‐seeding common strain endophytic pastures with livestock‐safe novel endophyte/grass associations to alleviate fescue toxicosis is unlikely to promote markedly higher populations of plant‐feeding insects.     

草坪地下害虫蛴螬的生物防治研究进展

蛴螬是草坪上最重要的一类地下害虫 ,对草坪的危害极大。文章综述了应用昆虫病原线虫、昆虫病原细菌、昆虫病原真菌、原生动物、昆虫病毒和寄生性、捕食性天敌昆虫等生防因子防治草坪害虫蛴螬的研究进展 ,并对未来草坪害虫蛴螬防治的研究发展方向做了一些探讨。     

Susceptibility of Hoplia philanthus (Coleoptera: Scarabaeidae) larvae and pupae to entomopathogenic nematodes (Rhabditida: Steinernematidae, Heterorhabditidae)

Biological control potential of nine entomopathogenic nematodes, Heterorhabditis bacteriophora CLO51 strain (HbCLO51), H. megidis VBM30 strain (HmVBM30), H. indica, Steinernema scarabaei, S. feltiae, S. arenarium, S. carpocapsae Belgian strain (ScBE), S. glaseri Belgian strain (SgBE) and S. glaseri NC strain (SgNC), was tested against second-, and third-instar larvae and pupae of Hoplia philanthus in laboratory and greenhouse experiments. The susceptibility of the developmental stages of H. philanthus differed greatly among tested nematode species/strains. In the laboratory experiments, SgBE, SgNC, HbCLO51 and HmVBM30 were highly virulent to third-instar larvae and pupae while SgBE was only virulent to second-instar larvae. Pupae were highly susceptible to HbCLO51, HmVBM30, SgBE and SgNC (57–100%) followed by H. indica and S. scarabaei (57–76%). In pot experiments, HbCLO51, SgBE and S. scarabaei were highly virulent to the third-instar larvae compared to the second-instar larvae. Our observations, combined with those of previous studies on other nematode and white grub species, show that nematode virulence against white grub developmental stages varies with white grub and nematode species.     

Current issues involved with the identification and nutritional value of wood grubs consumed by Australian Aborigines

The so called witchetty grub is a publicized food source for Australian Aborigines. Despite heavy use, the identities and number of species consumed is still not known because of the lack of identified voucher specimens. Taxonomy based on adults makes identification of larval forms difficult. Dwelling in the root, trunks, and stems of woody plants, grubs are a reliable and highly valued food source that may be in decline. Much information on edible insects may already be lost in parts of Australia heavily settled by Europeans. However, there are many parts of Australia where information on edible insects is still strong and needs to be recorded accurately for long‐term use. Recent identification of “witchetty grubs” from the witchetty bush at Barrow Creek has revealed that those there, based on their DNA, are not Endoxyla leucomochla. As grubs are collected and eaten before they mature and scientific taxonomy is based on adults, there are many unanswered questions on the grub identification and biology, host plants, and plant and grub distributions.     

Molecular characterization and estimation of cellulolytic potential of gut bacteria isolated from four white grub species native to Indian Himalayas

An investigation was carried out to isolate, identify and molecularly characterize the cellulose-degrading bacterial isolates from the guts of four white grub species (Anomala bengalensis, Brahmina coriacea, Holotrichia longipennis and Holotrichia setticollis) native to Uttarakhand, Himalayas through 16S rRNA sequencing. A total of 178 bacterial strains were isolated from different gut compartments of selected white grub species, of which 95 bacterial isolates showed cellulose metabolizing activities in the CMC assay. Maximum degraders i.e., 38 were isolated from A. bengalensis, of which 18 were isolated from the fermentation chamber. The value of cellulolytic index ranged between 0.05 and 16 showing a variable cellulolytic activity by degraders. A total of 25 potent strains of cellulose-degrading bacteria recording cellulolytic activity > 1 were isolated and sequenced for 16S rRNA gene. Bacillus stratosphericus strain CBG4MG1 (10.78 ± 4.18), Bacillus cereus strain CBG2FC1 (10.33 ± 3.53), Bacillus sp. strain CBG3MG2 (7.28 ± 0.16) and Paenibacillus ginsengagri strain CBG1FC2 (5.66 ± 2.67) were the most potent cellulose-degrading bacteria isolated from the gut of B. coriacea, H. longipennis, H. setticollis and A. bengalensis, respectively. Thus, the cellulolytic bacteria isolated from the gut of selected white grub species may be good sources for profiling novel isolates for industrial use besides identifying eco-friendly solutions for agro-waste management.     

闽南旱地作物蛴螬发生及防治的研究

通过金龟子成虫在黑光灯下和田间的消长调查、蛴螬的田间定期挖查 ,初步摸清了闽南地区危害花生、大豆、甘薯、甘蔗等旱地作物的蛴螬种类有 2 6种 ,主要种类有 9种。明确了其主要蛴螬种类的生活习性与旱地作物互为相关。通过采用不同的药剂与不同方法进行防治试验 ,筛选出经济有效的药剂种类 ,并根据不同作物的生长特性和不同蛴螬种类的危害特点 ,确定了经济有效的防治适期 ,并制定了相应的防治技术措施