摘要:

Weather parameters during the same week and one, two, three or four weeks before were correlated with the population of earhead bug,Calocoris angustatuson different earhead stages of two hybrids, CSH 5 and K‐Tall, in main and ratoon crops. The weather factors in the different weeks contributing to the insect population varied with the stage of earhead, the hybrid and the nature of the crop (main or ratoon). In the main crop, the insect population at pre‐flowering, milky, dough and maturity stage was influenced by weather parameters one week before, the same, two and three weeks before respectively. Morning relative humidity was important in both hybrids at all stages, with a few exceptions. In the ratoon crop, the pre‐flowering and maturity stage populations were influenced by the weather parameters of the same week. The populations at milky and maturity stage were influenced by parameters four weeks and one week before the observations respectively. The factors influencing the population on CSH 5 and K‐Tall varied. In most cases morning relative humidity had a positive influence.

ISSN:0143-6147    

DOI:10.1080/09670878809371290

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Eleven okra lines collected from Imo, Anambra and Rivers States were evaluated in the glasshouse for resistance to S.derogata.The materials included four improved lines while the other seven were locally collected. The plants were grown for eight weeks in the glasshouse before they were infested for 2 days with 12 pairs ofS. derogatareared in the laboratory on 20% honey concentration. Damage by S.derogatawas recorded 14 days from introduction of the moths. The mean number of leaf rolls per plant showed that NHAE 47–4 and L‐O‐2 were highly susceptible while OP80, L‐O‐4 were the least susceptible.

ISSN:0143-6147    

DOI:10.1080/09670878809371291

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The abilities of six geographical strains of the rice weevil,Sitophilus oryzaeto oviposit and develop in five varieties of sorghum(Sorghum bicolor) wereexamined. The varieties varied in their susceptibilities to S.oryzaedamage and the strains varied in their abilities to attack sorghum. Variety by strain interactions were also demonstrated for numbers of eggs laid and numbers of F1 adults emerging. The importance of considering the variation between strains when assessing susceptibility of sorghum varieties to S.oryzaeattack is discussed.

ISSN:0143-6147    

DOI:10.1080/09670878809371292

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Data on shoot borer,Chilo infuscatellusSnell., infestation and granulosis virus infection were collected from sugarcane planted during early and late main seasons and special season on 45, 60, 75 and 90 days after planting. The shoot borer infestation varied significantly among seasons of planting and age of the crop. It was low in March‐April planted crop compared to December‐January and special season planted crops owing to higher rainfall. The infestation was more on 45 and 60 days old crop compared to 75 and 90 days. The seasons of planting, age of the crop and stage of the host larva failed to have any significant influence on the virus infection.

ISSN:0143-6147    

DOI:10.1080/09670878809371293

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The mortality of pearly scale cysts,Sphaeraspis salisburiensisand the emergence of adults from the cysts at different temperature and moisture conditions were determined. There was a differential response by the cysts to the different conditions. One hundred per cent cyst mortality after 1, 2 and 4 weeks was recorded at 30°, 0° and 10°C respectively. Adults developed at 25°C and at fluctuating temperatures (25°‐40°C). The percentage mortality of cysts initially exposed to low temperatures (‐10°, 10° and 15°) for 5 weeks and subsequently transferred to high temperatures (20°, 25° and 30°C) was determined.

ISSN:0143-6147    

DOI:10.1080/09670878809371294

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The relationship between the catch of maleSpodoptera litura(F.) moths in sex pheromone‐baited traps and the number of egg‐masses in groundnut crop at the International Crops Research Institute for Semi‐Arid Tropics Centre Patancheru, India was examined during the post‐rainy season of 1983. Significant positive correlations were found between the number of egg‐masses and the total number of male moths caught during the 7 days preceding the egg‐mass count. 75% of the variance in the egg‐mass counts and pheromone trap catches could be accounted for by the regression.

ISSN:0143-6147    

DOI:10.1080/09670878809371295

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An experiment was conducted at the Indian Grassland and Fodder Research Institute, Jhansi (U.P.) during the Rabi seasons of 1982–83 and 1983–84 to study the effect of different levels of nitrogen (25, 50 and 75 kg/ha), phosphorus (25, 50 and 75 kg P2O5/ha) and potassium (15, 30 and 45 kg K2O/ha) on the populations of mustard aphid and saw‐fly and the seed production of fodder mustard (Brassica campestrisL. var China cabbage). Higher doses of P2O5and K2O reduced the population of saw‐fly and aphid whereas nitrogen increased these pests. Seed production was increased with higher doses of all three fertilizers.

ISSN:0143-6147    

DOI:10.1080/09670878809371296

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The mites attacking Important plants in the North Eastern Hill region of India were surveyed for 3 years from 1984. The mites recorded belonged to three families: Tetranychidae, Tenuipalpidae and Eriophidae. The most common and widely distributed species wereEutetranychus orientalis, Tetranychus telarius, Tetranychus cucurbitaeandBrevipalpus phoeniciswhich attacked a number of vegetables and fruit trees. The total number of mite species recorded in Meghalaya were 10 on 28 plants, in Tripura 6 on 17 plants, in Manipur 5 on 14 plants, in Nagaland 3 on 7 plants, in Arunachal Pradesh 3 on 5 plants and Mizoram 3 on 6 plant species.

ISSN:0143-6147    

DOI:10.1080/09670878809371297

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Heliothis armigeraHbn. is a major pest on chickpeaCicer arietinumL. causing serious damage to foliage, flowers and seeds. Field studies during 1985–86 have shown that the nuclear polyhedrosis virus (NPV) applied at the rate of 250 LE (1·5 x 1012POB/ha) four times gave effective control of the pest and was comparable with the control achieved by endosulfan at 350 g a.i./ha by high volume application (500 litres spray fluid/ha). ULV application of NPV in 20% crude sugar (12·5 litres spray fluid/ha) was as effective as high volume application at the same dose of 250 LE/ha. Application of NPV 250 LE + endosulfan 175 g a.i./ha high volume gave the best results recording 1·58 larvae/20 plants, 4·2% leaf damage, 6·9% pod damage and 1159 kg grains/ha as against 3·75 larvae/20 plants, 4·9% leaf damage, 12·5% pod damage and 925 kg/ha of grain in NPV high volume treatment. The untreated check recorded 20·75 larvae/ 20 plants, 18·0% leaf damage, 26·4% pod damage and 590 kg grain/ha. The different adjuvants tested in the high volume application of NPVviz.crude sugar 0·5%, peanut oil cake 1%, chickpea flour 1 % or a combination of these did not improve the efficacy of the virus in the two field experiments.

ISSN:0143-6147    

DOI:10.1080/09670878809371298

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Twenty four varieties of cowpea were evaluated for field resistance toAphis craccivoraKoch under natural infestation at Ile‐lfe, Nigeria. The varieties EW/1, TVu 1037, TVu 2896, TVu 2994 and TVu 3000 showed the lowest field infestation. This may be explained by antixenosis with respect to varietal selectionorfeeding and antibiosis. Screenhouse studies showed that the mechanism of resistance in TVu 1037, TVu 2896 and TVu 3000 includes antibiosis, manifested as high mortality of nymphs, reduced lifespan and low fecundity of adults.

ISSN:0143-6147    

DOI:10.1080/09670878809371299

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor