摘要:

Arthropod pests and their effect were studied over two years on three melon crops: watermelonCitrullus vulgaris(L), Sardah and Garma, cultivars of muskmelonCucumis melo(L). Melon fly,Dacus cucurbitaeCoquillett; Baluchistan melon fly,Myiopardalis pardalinaBigot and melon aphid,Aphis gossypii(Glover) where the major insect pests. Sardah and Garma fruits were damaged more than watermelon. Predacious insects appeared late in the season, and were not of much value in control. Pest attack was higher at Kandahar than at other sites.

ISSN:0143-6147    

DOI:10.1080/09670878709371110

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The incidence of sweetpotato weevil infestation on sweet potato in relation to frequency of hilling‐up the plant was investigated over two seasons in the Philippines. Planting date had pronounced effect on both damaged marketable and total tubers and the actual yield (weevil‐damaged + non‐weevil‐damaged). Hilling‐up significantly reduced the proportion of both marketable and total (marketable + non‐marketable) weevil‐damaged tubers. Hilling‐up the plants twice, i.e., at 4 and 6 weeks after planting, was adequate to reduce the damage of the weevil to the tuberous roots of sweet potato.

ISSN:0143-6147    

DOI:10.1080/09670878709371111

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A disease‐like injury on cassava(Manihot esculentaCrantz) due to feeding byPseudotheraptus devastansDist. is described. Experimental data reveal that cassava plants are more severely damaged by males than females. Observations indicate the existence of a preferential feeding habit ofP. devastansfor certain clones, and there were linear relationships between the number of lesions and the insect population, with some relationship to duration of feeding.

ISSN:0143-6147    

DOI:10.1080/09670878709371112

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This article reviews the aphid species associated with the potato crop in India, their population dynamics, control and the residues of granular and foliar systemic insecticides used.

ISSN:0143-6147    

DOI:10.1080/09670878709371113

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The economic injury level of maize stem borer,Chilo partellus(Swinhoe) was determined for two maize varieties, Basi Local (susceptible) and CM‐500 (resistant). One‐day‐old first instar stem borer larvae, in varying densities, were released on 12‐, 17‐, 22‐ and 27‐day‐old plants. Irrespective of larval density, the maximum yield loss was encountered when plants were 12 days old. The yield loss gradually decreased in CM‐500 as well as in Basi Local as the crop grew older, though it was more steep in. CM‐500. A positive relationship was observed between larval density and yield loss in 12‐ and 17‐day‐old crop. With 22‐ and 27‐day‐old plants maximum yield loss was caused by 20 larvae/plant, instead of 24 larvae/plant. The economic injury level (EIL) was found to increase as the crop stage increased. In case of Basi Local. EIL was 1.24, 1.38, 2.56 and 3.36 larvae/plant for 12‐, 17‐, 22‐and 27‐day‐old crop. On the other hand CM‐500 required 1.16, 1.17, 8.86 and 14.13 larvae/plant for 12‐, 17‐, 22‐ and 27‐day‐old crop. A significant difference in yield loss in Basi Local and CM‐500 was found when 20 larvae/plant were released on 22‐day‐old crop.

ISSN:0143-6147    

DOI:10.1080/09670878709371114

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The rice gall midgeOrseolia oryzae(Wood‐Mason), one of the major insect pests of rice, has several epidemics in Chhattis‐garh region of Madhya Pradesh, India. In the present investigation attempts were made to study the seasonal incidence of the pest along with its natural enemies and weather factors duringKharif1983 at Zonal Agricultural Research Station, Raipur. The major active period of the gall midge was 36th to 43rd week, i.e. September through October, as monitored by field incidence of the pest. The results revealed that parasitoidsPlatygaster oryzae(Cameron) andNeanastatus grallarius(Masi), and one predatorPaederus fuscipesCurtis were active in the 40th to 47th week, i.e. October through November.

ISSN:0143-6147    

DOI:10.1080/09670878709371115

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Studies on the antibiotic effect of the maize varieties Antigua Gr.1, Ganga 5, JML22, and JML605 (less susceptible), Vijay, Ageti 76, Partap, Sangam (moderately susceptible) and Basi local (more susceptible) on various aspects of the biology of the maize borer,Chilo partellus(Swinhoe) at Ludhiana during 1979 and 1980, suggested that, during both years of testing, the less susceptible varieties generally show more antibiosis. These varieties reduced larval survival (11–17%), larval weight (51–60mg/larva), pupal weight (49–52 mg/pupa), pupal formation (9–11%), egg viability (78–83%), adult longevity (47–81 h in males and 62–99 h in females) and growth index (0.3–0.4). The corresponding values for the more susceptible variety, Basi local, were 26%, 65mg/larva, 65mg/pupa, 18%, 87%, 132h in males and 137 h in females, and 0.7, respectively. The larval period (26 days) and the pupal period (6 days) were prolonged (25–31 days and 7–8 days, respectively) on Basi local; pupal survival was not affected. On the less susceptible varieties, males outnumbered females, while on the moderately susceptible and susceptible varieties, females outnumbered males. The maize borer multiplied 1.1–1.4 times in one generation on the less susceptible varieties, compared with 2–3 times on the moderately susceptible and susceptible varieties. The implications of the results are discussed.

ISSN:0143-6147    

DOI:10.1080/09670878709371116

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The cassava mealybugPhenacoccus manihotiMat‐Ferr is new to Sierra Leone where it has quickly achieved key pest status. It is firmly established in the Western Area of the country and is progressively extending to the provincial areas. All available cassava varieties are susceptible to the insect, and the damage is especially significant on the late planted crop. Biological control, for example by ground release of exotic hymenopteran parasitoids in the dry season, is recommended as a long lasting strategy to undermine the pest's status as a limiting factor to food production.

ISSN:0143-6147    

DOI:10.1080/09670878709371117

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The results of a survey of insecticide resistance in the cotton whitefly(Bemisia tabaciGenn.) to some of the commonly used insecticides, or insecticide mixtures, in the Sudan Gezira Scheme, disclosed that high levels of resistance exist in the Scheme's whitefly populations. The resistance ratios of the scheme populations, relative to a susceptible strain, for the adults and nymphs, respectively were as follows: dimethoate, 454 × and 257 ×; endosulfan, 364 × and 5 ×; dimethoate/endosulfan mixture, 10 × and 7 ×; methomyl, 8 × and 8 ×; amitraz, 6 × and 2 ×; and amitraz/endosulfan mixture, 5 × and 3 ×. The adults of an out‐of‐season strain of the cotton whitefly exhibited moderate levels of resistance to amitraz (7 ×), amitraz/endosulfan mixture (3×), and endosulfan (3×). The nymphs of this strain showed resistance to dimethoate (25 ×), amitraz (8 ×) and dimethoate/endosulfan mixture (3 ×). Adult whiteflies were always found to be more susceptible than nymphs and the resistance ratio of the adults was generally higher than that of the nymphs.

ISSN:0143-6147    

DOI:10.1080/09670878709371118

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The h.v. (312 litre/ha) sprays were applied by using a manually‐operated knapsack sprayer. The l.v. (31 litre/ha) and u.l.v. (undiluted) sprays were applied by using a motorized‐knapsack sprayer. The h.v. (e.c.) and the u.l.v. (l.v.c.) treatments were at par, and gave better performances than the l.v. (e.c.) treatment, on the basis of rosetted flowers, infestation of green bolls, shed fruiting‐bodies, harvested bolls and loculi, and population of bollworms in the shed material and seed‐cotton. The least effective treatment was that of the u.l.v. (e.c). The highest yield of 1408–1563 kg/ha of seed‐cotton was also obtained in the h.v. and the u.l.v. (l.v.c.) treatments, compared to 1363 kg/ha in the l.v., and 1211 kg/ha in the u.l.v. (e.c), treatments.

ISSN:0143-6147    

DOI:10.1080/09670878709371119

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor