摘要:

Field trials were conducted to evaluate the relative efficacies of three different methods of insecticide application against cotton insect pests by use of the electrodyn, Ulva micron and conventional knapsack sprayers. Use of the electrodyn resulted in the highest seed cotton yield in 1981, with an increased yield of 534.0 kg/ha over the control. In 1982 there was no significant (P=0.05) difference in the seed cotton yield obtained following use of any of the three sprayers. In 1985 however, insecticide application with the Ulva micron sprayer resulted in the highest seed cotton yield with a 592.0 kg/ha increase over the control. Seed cotton yields from farmers’ plots demonstrated the superiority of the electrodyn over conventional sprayers in controlling cotton pests. Based on the actual practical application of the three methods, it was concluded that the electrodyn is a more promising implement for insecticide spraying by small farmers than ultra low volume and knapsack sprayers.

ISSN:0143-6147    

DOI:10.1080/09670878709371146

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Bio‐efficacy of 15 insecticides was evaluated against the pest complex of okra in the semi‐arid region of Rajasthan during July‐October, 1984. Five sprays given at intervals of 15 days throughout the crop period indicated that fenvalerate (0.02%) was most effective, followed by permethrin (0.02%), cypermethrin (0.02%), carbaryl (0.10%), monocrotophos (0.04%) and dimethoate (0.03%), against leafhoppers, aphids and fruit borer. The maximm yield of marketable fruits was obtained with fenvalerate, followed by cypermethrin, carbaryl, monocrotophos and dimethoate treatments. Highest net‐profit of Rs. 4890.00 was also recorded with fenvalerate treatment, followed by Rs. 4430.00 with carbaryl, Rs. 4148.00 with permethrin, Rs. 3977.00 with monocrotophos and Rs. 3053.00 with dimethoate treatments. A higher benfit cost ratio was found with carbaryl (1:9.78), followed by dimethoate (1:7.85), monocrotophos (1:5.18), methyl demeton (1:5.07), fenvalerate (1:3.43) and permethrin (1:2.41). These insecticides can also be used against insect pests of other vegetable crops of the season.

ISSN:0143-6147    

DOI:10.1080/09670878709371147

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Biochemical and pathogenicity tests identifiedErwinia chrysanthemias the causal organism of a serious corm and rhizome rot of banana in lowland Papua New Guinea. The pathogen was repeatedly isolated from diseased tissue and soil surrounding diseased plants, but not from healthy corms or field soil.E. carotovorasubsp.carotovorawas often a co‐isolate withE. chrysanthemibut pathogenicity tests indicated a minor role for this organism in the disease. Observations of disease incidence in 10 banana cultivars indicated significant differences in disease susceptibility between newly planted corms and established plants, diploids versus triploids and AAAversusABB genotypes.

ISSN:0143-6147    

DOI:10.1080/09670878709371148

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A survey was undertaken to observe the pevalence of granulosis viruses infecting sugarcane shoot borerChilo infuscatellusSnellen and internode borerC. sacchariphagus indicus(Kapur) in Tamil Nadu State and Union Territory of Pondicherry in India. Nine districts in Tamil Nadu and Pondicherry had the occurrence of shoot borer granulosis virus in all the locations surveyed ranging from 2.6 to 14.6%. In internode borerthe mortality varied from 3.8 to 31.5% in the eight districts of Tamil Nadu and Pondicherry.

ISSN:0143-6147    

DOI:10.1080/09670878709371149

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Apparently similar viruses were associated with two different disease symptoms in sunflower (Helianthus annuus)in Kenya, one a yellow blotch and the other a leaf crinkle. The virus occurred in all sunflower‐growing regions but the crinkle disease was confined to areas east of the rift valley. Disease incidence varied with locality and season. Mechanical transmission of virus from plants with either disease was possible, but the yellow blotch virus was also transmissible from an important alternate field host, TridaxprocumbensbyAphis gossypiito 23 species in three families. Partially purified preparations of virus made from mechanically inoculated seedlings affected with either symptom type contained 26 nm virus particles which, in ISEM tests, reacted with antisera prepared against six members of the luteovirus group.

ISSN:0143-6147    

DOI:10.1080/09670878709371150

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

For quantitative estimation of suceptibility to mango malformation, the highest ranking severity found in an accession was multiplied by the incidence of diseased plants, the product being the maximum disease index. Of 29 germplasms/cultivars rated, only three (Asaugia Davban, Langra Rampur and Malda Handle) were resistant (0% disease index). Popular cultivars such as Dashebri, Chausa, Langra Gorakhpur and Mallihabadi were found to be susceptible (>20% Dl).

ISSN:0143-6147    

DOI:10.1080/09670878709371151

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Fourteen fungicides both of systemic and non‐systemic types were evaluated for their effectiveness against rice seedling blight disease caused bySclerotium rolfsiiin the rice seedbeds of the boro season (November‐April). The fungicides were tested both for seed and soil treatment. Only Brassicol (PCNB) at 6 g/kg seed and 1.5g/m2seedbed and Vitavax‐T (Car‐boxin; thiram) at 2g/kg seed and 1g/m2seedbed effectively reduced disease severity. Seed treatment was found to be better than soil treatment in reducing seedling mortality.

ISSN:0143-6147    

DOI:10.1080/09670878709371152

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In studies on chemical weed control in some cruciferous crops, butachlor, fluchloralin and oxyfluorfen proved to be effective for transplanted knol khol (kohl rabi) both in terms of reduced weed dry matter and crop yield. For white radish, alachlor and butachlor at 2.0 kg, and fluazifop‐butyl* at 0.75 kg a.i./ha, were suitable herbicides. For red radish, alachlor, butachlor and fluchloralin were equally effective in controlling weeds when compared with hand weeded control. Fluazifop‐butyl controlled bothCyperus iriaand C.rotundusvery effectively. Generally, herbicide treatments were found to be more economical than hand weeding in all the three crops tested.

ISSN:0143-6147    

DOI:10.1080/09670878709371153

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The effect of different times of weed removal and the influence of some pre‐emergence herbicides on Soybean(Glycine max(L.) Merr.) were studied in four experiments in the vertisols of central Sudan. Full season competition of weeds reduced seed yield by 78–100%. Delay in first handweeding beyond 30 days after sowing adversely affected the soybean yield and three hand weedings at intervals of 15 days were necessary for adequate weed control and high yield. Both unweeded and late weeding reduced N% in leaves at flowering to about 1.6% compared with 2.8% with frequent weeding. The most successful herbicides for control of the dominant weedsEchinochloa pyramidalis(Lam.) Hitch and Chase andRottboellia cochinchinensis(lour.) W. D. Clayton were oxadiazon at 1.43 kg/ha and oxyfluorfen at 0.48 kg/ha. Pendimethalin and metolachlor gave satisfactory control of most grasses (72–91%), but many broad leaved weeds were resistant to both herbicides. Metobromuron did not give effective weed control and caused severe damage to crop at seedlings stage.

ISSN:0143-6147    

DOI:10.1080/09670878709371154

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Habitats of aquatic weeds have been classified. Common weeds growing in each habitat have been listed. Emphasis has been given to describing the problems created by aquatic weeds in each habitat. Impact has been focussed on the effect of aquatic weeds on the national economy. Methods used in controlling weeds in each habitat have been described.

ISSN:0143-6147    

DOI:10.1080/09670878709371155

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor