摘要:

Among the major insect pests that attack potato, the Epilachna beetle,Epilachna vigintioctopunctatais very important in Asia. It is widely distributed in South and East Asia, Australia, America, and the East Indies. Commonly £ 12stigmaandE.28punctata, E. ocellataandHenosepilachna sparsaattack sola‐naceous plants. The peak period of infestation varies with’ the region, but the peak is in July‐August. The pest also feeds on brinjal (egg plant), tomato, tobacco, pumpkin and bitter gourd. The larvae and adults scrape the green matter from leaves and cause damage up to 80%. The morphology and biology are described. Among the various components of management, the predator reduviid bug,Rhinocoris fuscipes(Fab.) is recorded and seven larval parasites have been found, with 53–5–77–5% parasitization.Aspergillus flavusandBacillus thuringiensisare effective against different stages of the pest. Various chemicals including plant products have been evaluated and sprays of 0–5% carbaryl + molasses and quinalphos e.c. were found to be effective for 20 days. The repellent and antifeedant properties of neem, mahua and groundnut cakes have also been established. Varying degrees of malformation were observed after radiation by a 60 cobalt source.

ISSN:0143-6147    

DOI:10.1080/09670878909371418

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The incidence and diapause of cereal stem borers, and the role of crop residues in the carry‐over of these pests on Rusinga Island in Kenya were investigated. The predominant stem borer infesting sorghum, the major cereal in this area, wasBusseola fusca.Another stem borer,Chilo partellusoccurred in very small numbers. However, a short‐rain sorghum or maize crop can be subjected to heavy infestation by both borers. The majority of the second generationB. fuscaon the long‐rain sorghum crop survived the off‐season (July/August‐February/March) as diapausing larvae in crop residues (stalks and stubbles).C. partelluson the other hand, survived mostly as an active population, but in low numbers. The number ofB. fuscain a 50 m2area of crop residues was reduced from 200 in September to 13 in February, the end of the off‐season. This small population mostly at the base of the stubbles appeared to be the source of infestation of the newly planted crop, and may have the potential of causing heavy infestation as each of the female moths emerging has an average fecundity of 650 eggs. Termination of diapause inB. fuscastarted in late November and reached a peak in February. Rainfall did not appear to be the main factor in the termination of diapause. On these observations it is clear that destruction of diapausingB. fuscaduring land preparation for the long rainy season crop, preferably by burning the stubbles, would be an effective cultural control method on Rusinga Island.

ISSN:0143-6147    

DOI:10.1080/09670878909371419

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Sampling with quadrats of 0.25 m2in Madagascan rice fields reveals that egg batches of the African White Stem Borer,Maliarpha separatellaRAG. are distributed at random. The physical size of the sampling unit is selected because of practical rather than ecological considerations. According to the enumerative sampling plan at least 40 quadrats should be taken per field to satisfy precision requirements. Sequential binomial sampling with constant error rates is more cost efficient and decision making with respect to an action threshold is possible with 12 quadrats or more at a critical time. For regional estimates a stratified random sampling procedure is proposed.

ISSN:0143-6147    

DOI:10.1080/09670878909371420

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A number of observations on the population dynamics ofAnastrepha obliquaassociated with a mango plantation in Orotina, Costa Rica were carried out. (a) After eleven months sampling with McPhail traps, 54.63% of adults captured wereA. serpentina41.73%A. obliqua3.56%A. striataand 0.08%A. balloui.The period of maximum abundance of these species coincides with the fruiting season of the respective host plants,A. serpentinacoincided with the fruiting of several Sapotaceae,A. obliquawith some Anacardiaceae andA. striatawith some Myrtaceae. However all adults from infested mangoes wereA. obliqua.(b) The phenology of adult emergence ofA. obliquafrom the ground was observed in 1986. Most emerge just after the first rains; this coincides with the fruiting season, and emergence continues many weeks after the crop is over. (c) To determine the dispersal ofA. obliqua633 young adults were marked and released in the mango plot. Only one marked adult was recaptured five weeks later. Adults showed a tendency to disperse from the original plot.

ISSN:0143-6147    

DOI:10.1080/09670878909371421

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Seeds of 22 rice strains carefully selected for resistance by continuously testing under high gall midge pressure at Cuttack (Orissa) through 1979–198’ and three such strains from Raipur (Madhya Pradesh) were assembled along with susceptible standardJayaand were simultaneously tested at both locations (Cuttack and Raipur) against the Asian rice gall midgeOrseolia oryzaeWood‐Mason in wet season 1985. Eighteen entries proved resistant at both locations. WhileAsha, UshaandSamrudhiwere resistant at Raipur and susceptible at Cuttack,ShaktiIR.36, IR.50,DayaandPratapwere resistant at Cuttack and susceptible at Raipur, based on which characterization of the Cuttack (Orissa) and Raipur (Madhya Pradesh) gall midge biotypes was proposed. In gall midge biotypes testing, meticulous selection of only such entries with consistently proven resistance to gall midge at least at one location, carrying forward seed from resistant plants only each season under high gall midge pressure (with 100% seedling/hill infestation in oft repeated susceptible check) and classification of test entries at the strain's level either as resistant or as susceptible without scope for the third ‘moderate’ category to intervene, generally ignored by earlier workers, were stressed.

ISSN:0143-6147    

DOI:10.1080/09670878909371422

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Leafhoppers of the cicadellid subfamily Idiocerinae are well known pests of mango in the Oriental region. These and other Auchenorrhynchous Homoptera recorded on mango throughout the world are reviewed.

ISSN:0143-6147    

DOI:10.1080/09670878909371423

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0143-6147    

DOI:10.1080/09670878909371397

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor