ISSN:0143-6147    

DOI:10.1080/09670878709371166

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In recent years, nationwide insecticide resistance management (IRM) strategies in Zimbabwe, Egypt and Australia have successfully overcome existing resistance problems on cotton and prevented further outbreaks in some key pests. These strategies, which rely heavily on pragmatic assumptions regarding the efficacy of counter‐measures and the biology of the pest, relate little to theoretical models of resistance management whose tenets have so far not been experimentally appraised. These IRM strategies are compared with a simple but rigid programme used throughout Francophone countries of Africa that has successfully controlled the pest complex on cotton and increased yield without eliciting resistance in any pests. We examine the motivations, philosophies and logistics of these control programmes on cotton, and outline scope for improvements to existing and future IRM.

ISSN:0143-6147    

DOI:10.1080/09670878709371167

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The importance ofCreontiades pallidus(Rambur) as a pest of cotton grown along the Euphrates river in Syria, was evaluated during 1979 to 1983. Cotton plants grown in cages and exposed to large numbers of the species suffered a yield loss of 54.3%. In field trials, shedding of fruiting bodies was significantly higher in locations with large populations ofC. pallidusthan in areas where infestations were low. A mean population level of seven specimens per 50 sweeps, from early July till mid‐August, resulted in a yield loss of 50.4%. Control is recommended whenC. pallidusreaches a level of seven specimens per 50 sweeps in June or July, but control is not justified when this pest is found in August or later.

ISSN:0143-6147    

DOI:10.1080/09670878709371168

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Studies on the relative occurrence of the leaf‐gall midge (Procontarinia matteianaKieffer and Cecconi) on different varieties of mango cultivated in south Gujarat were carried out in 1984 and 1985. A locational survey was made at 17 different places in various talukas of District Valsad, to determine the relative infestation of leaf‐gall midge on Alphonso, Kesar and Raja‐puri, the most commonly cultivated mango varieties in south Gujarat; the survey indicated that the order of these three varieties, based on the average percentage of leaves damaged by the pest, was Alphonso (47.70%), Kesar (27.21%) and Rajapuri (25.80%), with an average of 20.12,17.64 and 12.46 galls per leaf, respectively. Studies were also carried out to investigate varietal susceptibility to gall midge in 24 varieties cultivated at the Fruit’ Research Station, Gujarat Agricultural University, Paria. The pest was observed to be parasitized byChrysonotomyia pulcherrima(Kerrich);Synopeas mangiferaeAustin andInostemma oculareAustin.

ISSN:0143-6147    

DOI:10.1080/09670878709371169

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In a field study of the effects of plant densities and carbofuran on damage byDiopsis thoracicaWestwood andMaliarpha separatellaRagonot, significant increases were recorded in the percentage of dead hearts and bored stems in widely spaced rice plants. Carbofuran treatments resulted in significant control of borers, the best treatment being that covering early growth up to 40 days after transplanting. There was a significant depression of yield components and total yield with closer spacing. Yield increases of 59%, 32% and 55% for the 1983 planting, and 55%, 35% and 50% for the 1984 planting, were recorded when carbofuran was applied to cover the periods 0 to 40, 40 to 80, and 0 to 80 days after transplanting, respectively.The percentage of dead hearts and bored stems increased with increasing seedling density. The yield components, however, did not show any significant differences.

ISSN:0143-6147    

DOI:10.1080/09670878709371170

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A survey for resistance in the cotton whitefly,Bemisia tabaci(Genn.), to chlorfenvinphos, chlorfenvinphos+endosul‐fan, methomyl+endosulfan, deltamethrin, and deltamethrin + endosulfan, was carried out during the season 1983/84. On the basis of LC50adults and nymphs of the Barakat Block population (Sudan Gezira Board) evolved resistance ratios (RR'S) to chlorfenvinphos (10.5‐ and 5.61 x); chlorfenvinphos + endosulfan (5‐and 4.28 x); deltamethrin (25‐ and 4.43 x) and deltamethrin + endosulfan (2.5‐ and 21.68 x), respectively. The study also showed that resistance can spread to neighbouring populations to unexposed insecticides and that resistance can develop to chemicals that have never been applied in the scheme. All three populations showed heterogeneity with regard to their susceptibility to the test insecticides.

ISSN:0143-6147    

DOI:10.1080/09670878709371171

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Guava fruit flies,Anastrepha striataSchiner, were trapped from April to November 1985, in standard McPhail glass jar traps baited with a solution of 20 g ofTorulayeast (type ‘B') and 18 g of sodium borate (borax) per liter of water at Guacimo (Limón Province) and at the Biological Station Finca La Selva (Heredia Province), Costa Rica, on the Mesoamerican isthmus. Traps were arranged respectively in a vertical and horizontal position in mature guava trees,Psidium guajavaL (Myrtaceae), 3–10 m and 2–3 m above ground level. A pronounced vertically differentiated distribution in the occurrence ofA. striatawas found during the wet season. At both study sites >85% of flies collected in the vertically hung traps were found at a height of 6 m or more above ground level. Differences in relative humidity and transient light between understory and canopy levels in the guava orchards are proposed as possible explanations for this vertical distribution.

ISSN:0143-6147    

DOI:10.1080/09670878709371172

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Liriomyza trifoliiBurgess had first been reported from Senegal in 1980. Field surveys in 1982 revealed its presence in all vegetable growing areas of the country, heaviest damage being registered in the Cap Vert. Five indigenous eulophids (larval parasitoids) plus five other rare parasitoids, frequently parasitized over 90% of the flies. These rates were higher in insecticide free fields, and very much above the 30–40% reported for 1981. The most important parasitoids wereHemiptarsensus semialbiclava(Girault), which dominated in the second half of the dry season, and twoChrysonotomyiaspp., which were more abundant in the rainy season. Surveys for exotic parasitoids indicatedDiaulinopsis callichromaCrawford from Trinidad to be a promising species for introduction in the New World. This parasitoid, together with eight other chalcidoids (mostly larval parasitoids) and two braconids (larval‐pupal parasitoids), were collected in the field or received from established insectary cultures. They were studied and shipped for rearing and release in Senegal. Nine species were released at the end of 1982 and in 1983. Many were recovered shortly after release, but onlyOpius dissitusMuesebeck was recovered in later samples and became relatively abundant.

ISSN:0143-6147    

DOI:10.1080/09670878709371173

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A key is presented to aid the identification of pupal cases of 46 species of whitefly often found infesting economic plants around the world. The general pupal case morphology of each species is illustrated, together with more detailed figures of some key characters. The key is designed for use with slide‐mounted specimens, and techniques for their preparation are described. The synonymy ofBemisia hancockiwithB. aferis discussed.

ISSN:0143-6147    

DOI:10.1080/09670878709371174

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The five synthetic pyrethroids cypermethrin‐1, cypermethrin‐2, deltamethrin, fenvalerate and FMC 54800, were evaluated under greenhouse and field conditions to determine their efficacy in preventing tungro infection and in reducing the incidence of tungro disease. Cypermethrin (1 and 2) and deltamethrin killed the vector,Nephotettix virescenswithin 7 minutes and prevented tungro infection under greenhouse conditions; the performance of these insecticides was also better under field conditions. Grain yields were higher in plots treated with these insecticides than in the control plot, or in plots treated with other insecticides, in the cultivar Taichung Native 1. In the cultivar Ratna, these insecticides, plus fenvalerate and carbofuran (check insecticide), had an equivalent effect. The vector population in the plots treated with cypermethrin (1 and 2) and deltamethrin was eliminated. There was a negative correlation between the rate of tungro infection and grain yield, and a positive correlation between vector population and disease incidence.

ISSN:0143-6147    

DOI:10.1080/09670878709371175

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor