ISSN:0143-6147    

DOI:10.1080/09670878709371100

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new bacterial disease of tobacco, not previously reported was found in Karnataka. Studies on the disease initiated to identify the causal agent the factors which predispose the plants to epidemics, and control of the disease, revealed that it occurs in epiphytotic form following heavy rains after the crop has been topped, and is more severe in thicker leaves. The primary source of inoculum is the soil, and secondary spread takes place by rainwater splashing from infected to healthy plants. The disease is found predominantly in beedi tobacco and causes severe damage to the crop resulting in economic loss in yield. The causal organism isErwinia chrysanthemi. In vitroevaluation of chemicals showed that streptomycin sulphate + chlorotetra‐cycline (Streptocycline), streptomycin sulphate (Ambystrin) and streptomycin sulphate + oxytetracycline (Paushamycin) were effective in control of the bacterial disease.

ISSN:0143-6147    

DOI:10.1080/09670878709371101

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Use of grass mulch as a means of reducing soil splash and hence secondary spread of black rot of cabbage through the hydathodes was as effective as Cobox (50% Cu) in the management of the disease and increase of yield. Black plastic mulch on the other hand gave no better results than the untreated controls.

ISSN:0143-6147    

DOI:10.1080/09670878709371102

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Field experiments were carried out in the years 1980–81 and 1981–82 to evaluate various herbicides for weed control in pea(Pisum sativumL.) at Jullundur, Punjab, India. Pre‐emergence application of metribuzin at 0.25 kg a.i./ha, terbutryn at 0.8 and 1.2 kg a.i./ha, methabenzthiazuron at 1.75 kg a.i./ha and nitrofen at 0.5 kg + methabenzthiazuron at 0.6 kg a.i./ha gave best weed control, reduced the dry matter of weeds and produced green pod yield comparable to hand weeded control. Higher levels of metribuzin and metoxuron showed phytotoxicity to peas.

ISSN:0143-6147    

DOI:10.1080/09670878709371103

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The effect of butachlar, oxadaiason, pendimethalin, avirosan, bentazon and their combinations for control of barnyard grass and umbrella sedge in rice (Oryza sativaL.) was studied in two field experiments at the Experimental Farm of the National Research Centre at Shalakan, Kalubia Governorate; Egypt, during 1982 and 1983. The differences in response among weeds and rice to post‐emergence herbicides and their combinations were very variable. The combination herbicides: pendimethalin at 0.83 kg + bentazon at 1.44 kg/feddan* butachlor at 1.0 kg + pendimethalin at 0.83 kg/feddan, oxadiaton at 0.5 kg + pendimethalin at 0.83 kg/feddan and avirosan at 0.5 kg + bentazon at 1.44 kg were very effective againstEchinochloa crus‐galli.Oxadiazon at 0.5 kg and avirosan at 0.5 kg as well as the combination of Butachlor at 1.0 kg + oxadiazon at 0.5 kg or Avirosan at 0.5 kg and avirosan at 0.5 kg + bentazon at 1.44 kg/ feddan gave the best weed control againstCyperusdifformis. All combination herbicides as well as the hand weeded treatment gave superior rice yields over those of the single herbicidal treatments.

ISSN:0143-6147    

DOI:10.1080/09670878709371104

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Two field experiments were conducted at Ngala in the Lake Chad Basin during the wet seasons of 1981 and 1982 to investigate weed competition as well as chemical and manual weed control in irrigated cotton (Gossypium hirsutumL.) var. Acala 1517C. Pre‐emergence herbicides and their mixtures were tested in replicated, randomized block trials in which the cotton variety was grown 30 cm apart on 90 cm ridges and fertilized with 50 kg N/ha and 40 kg P2O5/ha. The results showed the importance of early weed competition in irrigated cotton. Weed control 14 days after cotton emergence produced optimum growth and yield. Subsequent weeding delay in 7‐day increments restricted crop growth and reduced yield significantly. Unweeded cotton suffered an average yield loss of 82.0%. Yields of plots treated with fluridone at 1.0 kg a.i./ha and fluometuron at 3.0 kg a.i./ha respectively applied 1 to 2 days after sowing were significantly higher than the yield of the untreated plots and plots hand weeded once later than 21 days after crop emergence. Plots hand weeded once however, yielded significantly higher than the untreated plots.

ISSN:0143-6147    

DOI:10.1080/09670878709371105

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Field trials were conducted to test the efficacy of four herbicides applied alone and in combination on weeds and chickpea for three seasons. Application of fluchloralin at 1.0 kg and pendimethalin at 1.5 kg/ha as pre‐plant and pre‐emergence proved as effective in weed control as their combination. All herbicide treatments resulted in significantly lower population and dry weight of dominant weeds likeChenopodium albumandVicia sativaas compared to weedy plots. Application of fluchloralin and pendimethalin alone at 1.0 and 1.5 kg/ha, respectively, and combination of fluchloralin + pendimethalin and fluchloralin + metribuzin at higher rates produced better growth and reproductive characters of crop than their combinations at lower rates and weedy control plots. Metribuzin at 0.5 kg/ha also produced significantly better growth and yield of chickpea than weedy plots. Grain yield of above herbicide treatments did not differ significantly from weed free yields.

ISSN:0143-6147    

DOI:10.1080/09670878709371106

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Critical period of crop/weed competition was studied in upland rice during monsoon season from 1981 to 1983.Echinochloa colonum, Seirpus grossus, Dactyloctenlum aegyptium, Cyperus rotundus, C. iriaandTrianthema monogynawere the major weed species. Competition from weeds during the first 15 days after sowing (d.a.s.) had no significant effect on the grain yield of rice. Competition beyond 15 d.a.s. caused drastic reduction in the grain yield. Grain yield of rice Increased significantly with the increase in the duration of weed‐free period up to 45 d.a.s. during two years. However, further increase in the weed‐free period up to 60 d.a.s. caused significant improvement in the grain yield of rice in only one year. Weeds emerging after 45 d.a.s. were lower in density and their growth was suppressed by the crop. Density of weeds emerging between 15 and 30 d.a.s. was high and could compete with the crop resulting in reduced grain yields. The period during 15 to 45 d.a.s. was found to be the most important for crop/weed competition.

ISSN:0143-6147    

DOI:10.1080/09670878709371107

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The rustPuccinia canaliculata(Schw.) Lagerh. is a potentially important component of integrated weed management systems (IWMS) for the control ofCyperus esculentusL (yellow nutsedge). The effect ofP. canaliculataandP. canaliculatain combination with the herbicides imazaquin, glyphosate, paraquat, bentazon, or metribuzin, on C.esculentusreproductive and growth parameters, are reported. Significant rust‐herbicide interaction was demonstrated for bentazon, imazaquin, and metribuzin.

ISSN:0143-6147    

DOI:10.1080/09670878709371108

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The mango nut weevil,Sternochetus gravis(F.) is an important pest, and control with insecticides is difficult and impracticable. Treatment by clean cultivation reduced fruit attack from 87% (untreated) to 68%, by stirring the soil under trees to 78%, and handpicking of adults which had ascended the trees was least effective. In combination the three treatments reduced attack to 24%.

ISSN:0143-6147    

DOI:10.1080/09670878709371109

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor