Field Evaluation of a Commercial Formulation of the Spodoptera exigua (Lepidoptera: Noctuidae) Nuclear Polyhedrosis Virus for Control of Beet Armyworm on Vegetable Crops in Thailand

Small - scale field trials were conducted in the Kanchanaburi and Ratchaburi provinces of Thailand between December 1994 and March 1996 to gather efficacy data to support a registration dossier for a commercial formulation of a nuclear polyhedrois virus of beet armyworm , Spodoptera exigua, under the tradename Spod - X . A liquid concentrate formula tion of Spod - X was compared with two commercial standards , Bacillus thuringiensis subsp . aizawai (CenTuri 3 . 5 WDG) and the insect growth regulator tebufenozide (Mimic 20F , a benzoylhydrazine ecdysone agonist) , for control of beet armyworm on garden pea , Chinese kale , shallot and table grape . Spod - X applied at 4 - day intervals at 3 . 1 - 12 . 5 1011 occlusion bodies (OBs) ha 1 in a spray volume of 625 - 1000 l ha 1 provided excellent control of beet armyworm on garden pea and grape (75 - 100 % reductions) after the second application . On Chinese kale and shallot , rates of Spod - X in the rate 5 - 60 1011 OBs ha 1 sprayed every 4 days in a spray volume of 1000 l ha 1 provided significant protection from infestation of beet armyworm over the growing season; however , efficacy was poor to moderate . Tank - mixing Spod - X with the pyrethroid , deltamethrin (Decis3EC) , did not improveefficacy on shallot;however , combinations of virus and B. thuringiensis or tebufenozide achieved commercially acceptable levels of crop protection on Chinese kale compared with virus alone . Lower levels of control and crop pro tection observed with all materials on Chinese kale and shallot reflect , in part , the tendency of S. exigua larvae to feed within sheltered sites and directly damage marketable plant parts . In general , all rates of Spod - X performed as well as , or better than , the B. thuringiensis standard (56 . 3 - 105 g ha 1 a.i.) on all crops tested . In general , reductions of beet armyworm larval populations and plant damage provided by all labeled rates of the chemical standard , tebufenozide (125 - 250 g ha 1 a . i .), were marginally greater than all rates of Spod - X tested . On crops such as pea and grape , where beet armyworm predominately feed on exposed leaf surfaces , our data unequivocally support the use of Spod - X for cost - effective , season - long pest management . Strategies to improve the efficacy of virus on shallot and kale are discussed .     

AN UNUSUAL PHYCOCYANOBILIN-CONTAINING PHYCOERYTHRIN OF SEVERAL BLUISH-COLORED,ACROCHAETIOID, FRESHWATER RED ALGAL SPECIES1

The reproductive biology and phycobiliproteins of four different culture isolates of the freshwater algae Audouinella and‘Chantransia’were investigated.‘Chantransia’sp. (3585/UTEX 2623) and Audouinella macrospora (Wood) Sheath et Burkholder (3394,3395) from California and Minnesota reproduced only by monospores. However, A. macrospora (3603/Necchi 1) reproduced by monosporangia that formed successive generations of the Audouinella phase, and Batrachospermum shoots developed from the basal and erect systems. The major light-harvesting phycobiliprotein in all of these isolates was a phycocyanobilin-containing phycoerythrin not previously detected in red algae or cyanobacteria. As in the commonly found R- and B-phycoerythrins, Audouinella phycoerythrin had a native molecular mass of ～ 240,000 and was made up of α, β, and γ subunits. Audouinella phycoerythrin carried two phycoerythrobilins on the α subunit; one phycourobilin, one phycoerythrobilin, and one phycocyanobilin on the β subunit; and one phycourobilin and two phycoerythrobilins on the γ subunit. With excitation at 495, 563, or 603 nm, the fluorescence emission peak of Audouinella phycoerythrin was at 626 nm, showing that phycocyanobilin was the terminal energy acceptor.     

Effect of a membrane interactive peptide on plant cells of canola (Brassica napus) and two fungal pathogens

Summary A membrane interactive peptide was toxic to microspores, pollen and protoplasts of canola in the 1–5 µM concentration range. Similarly, at 5.0 µM the peptide completely inhibited germination of conidia ofVerticillium albo-atrum; however, when tested with conidia of a virulent isolate of blackleg (Leptosphaeria maculens), a fungal pathogen of canola, much higher levels (>30 µM) of the peptide were required to reduce or arrest germination and growth of the conidia. When testing the relative toxicities of novel peptides on plant cells and their pathogens, pollen germination is a simple, rapid and reliable alternative to protoplasts.     

Se和V_E与克山病

以克山病病区粮配成基础饲料,另在基础饲料中分别补充Ｓｅ或ＶＥ,或Ｓｅ＋ＶＥ喂养大鼠,在细胞及亚细胞水平上以Ｃａ代谢为主研究并比较了Ｓｅ和ＶＥ在克山病病因中的作用。测量了心肌细胞和心肌线粒体的Ｃａ代谢及有关指标、心肌线粒体能量转换功能及心肌组织自由基含量。结果表明,在低Ｓｅ病区粮中补充Ｓｅ或ＶＥ均能在一定程度上预防病区粮中致病因素对心肌细胞及线粒体的损伤;并且补充Ｓｅ或ＶＥ均能使心肌组织中自由基含量减少。提示Ｓｅ和ＶＥ是通过清除体内过量自由基预防细胞和线粒体的损伤的。但值得注意的是,实验中所用病区粮ＶＥ含量不低于甚至高于非病区对照粮,在低Ｓｅ情况下,所补ＶＥ的量需要相当大（如本实验中补充２００μｇ／ｇ）才能较明显地预防心肌细胞和心肌线粒体的损伤。通过对这些结果的分析,进一步肯定低Ｓｅ是克山病形成的重要因素之一。     

Breeding for resistance to downy mildews and stalk rots in maize

Summary The present review includes information on distribution, symptoms, inoculation techniques, disease rating, sources of resistance, genetics of resistance, breeding approaches for resistance, and the present status of resistance breeding with respect to Sclerophthora and Peronosclerospora downy mildews and Erwinia, Cephalosporium and Fusarium stalk rots. Some suggestions highlighting research gaps pertinent to future breeding strategies are mentioned.Publication No. 2993, Experiment Station, GB Pant University of Agriculture and Technology, Pantnagar, India     

Behavior of a Virus in a Symbiotic System, Paramecium bursaria—Zoochlorella

SYNOPSIS In a culture system of Paramecium bursaria , virus particles were found in large number. The particle was able to infect and multiply in certain cells of the zoochlorella, an intracellular symbiotic alga of P. bursaria. The infective particle, designated as zoochlorella cell virus (ZCV), was icosahedral and 120–180 nm in edge to edge diameter. The ZCV particle was found to differ from any of the already established viruses attacking the green and the blue-green algae. Within the system where P. bursaria cells were growing, ZCV particles were detected in the depression of the pellicle, among the cilia growing in the cytopharynx, and in the food vacuole of P. bursaria. ZCV particles were infective only for the zoochlorella cells which were recently released from the cytoplasm of P. bursaria. The multiplication process of ZCV comprised the adsorption of the particle to the cell wall of the zoochlorella, the penetration of nucleic acid into the host cell interior, the replication of viral constituents, the maturation of viral particles and their final release by the burst of the zoochlorella cell. ZCV particles appeared only in the cytoplasmic region of the zoochlorella cell in which many ribosomes were distributed. A possible ecosystem among the 3 members consisting of P. bursaria , zoochlorella and ZCV is discussed.     

Effects of organic amendments to soil on the rhizosphere microflora of antirrhinum infected withVerticillium dahliae Kleb.

Summary Organic (e.g. chitin, green manure, cellulose) amendments to soil induced quantitative and qualitative changes in the rhizosphere microflora of antirrhinum plants infected withVerticillium dahliae Kleb. Whereas reduction in disease severity occurred with chitin and green manure amendments, an increase in disease severity was observed with the application of cellulose. The reduction of the disease severity with chitin and green manure may be correlated with the increased population of actinomycetes in the antirrhinum rhizosphere.     

Genetic Evaluation and Utilization (GEU) program

Summary The Genetic Evaluation and Utilization (GEU) program of the International Rice Research Institute (IRRI) is an interdisciplinary program for the improvement of rice crops. Scientists trained in diverse disciplines such as plant breeding, plant pathology, entomology, agronomy, cereal chemistry, plant physiology, and soil chemistry work together and contribute their specialized skills to this joint endeavor. The program has five interrelated components: (1) germ plasm collection and conservation, (2) research in disciplinary areas, (3) development of improved germ plasm, (4) distribution, evaluation and exchange of germ plasm internationally, (5) training of young scientists.Over forty thousand rice varieties from different countries are being maintained in the IRRI germ plasm bank. These varieties have been screened for grain quality, resistance to various diseases and insects, and tolerance to various environmental stresses such as drought, high and low temperatures and problem soils. Donor parents for resistances to each of the problem areas have been identified. These parents were utilized for developing improved germ plasm. Varieties with resistance to as many as five diseases and five insect species have been developed. These multiple resistant varieties are grown on millions of hectares of rice land. Seeds of improved breeding materials are exchanged internationally and 194 scientists from different countries have been trained in rice improvement work.     

Inheritance of resistance to neonatal E. coli diarrhoea in the pig: examination of the genetic system

Summary Evidence is presented that a dominant allele, S, is expressed as a receptor for K88 on the brushborder surface of the pig intestinal cell. The homozygous recessive (ss) lacks this receptor. The receptor enables K88 — positive coliforms to adhere to the gut of the piglet which they must do if they are to cause neonatal diarrhoea. The homozygous recessive is thus a disease resistant animal.A possible reason for the persistence of the dominant (susceptible) gene is given.