Diseases observed on pigeonpea in East Africa

Pigeonpea is one of the important pulse crops in East African countries. Little is known about the prevalence of diseases and their relative importance in East Africa...

Effect of crop rotation and planting time on the incidence of wilt in lentil

In a crop rotation experiment, paddy and sorghum sown in the kharif reduced the lentil wilt in the succeeding rabi. In the same treatments higher grain yields were also recorded. Comparatively low incidence of wilt was recorded in December 15 planting than the earlier planting

Seed transmission of Fusarium udum in pigeonpea and its control by seed-treatment fungicides

F. udum was transmitted by infected seeds of 5 wilt susceptible pigeonpea cultivars collected from diseased susceptible pigeonpea cultivars collected from diseased plants. The fungus was not isolated from the wilt susceptible cultivars ICP 2376 and ICP 8518. Seed treatment with a mixture of benomyl and thiram completely eradicated the pathogen., 7 ref., F. udum was transmitted by infected seeds of 5 wilt susceptible pigeonpea cultivars collected from diseased susceptible pigeonpea cultivars collected from diseased plants. The fungus was not isolated from the wilt susceptible cultivars ICP 2376 and ICP 8518. Seed treatment with a mixture of benomyl and thiram completely eradicated the pathogen

Efficacy of metalaxyl for control of Phytophthora blight of pigeonpea

A seed dressing formulation of metalaxyl was evaluated under greenhouse and field conditions for the control of pigeonpea blight caused by Phytophthora drechsleri f. sp. cajani . Significant control of the blight (over 90 per cent) was achieved with metalaxyl (1.75 g a. i./kg seed) in a greenhouse trial for 30 days after planting. However, the fungicide was found ineffective against the disease in field tests

Control of Mycoflora Associated with Pigeonpea Seeds

Associated with the seeds of four field-grown pigeonpea cultivars, Alternaria sp., Aspergillus flavus, A. niger, Fusarium spp., and Rhizoctonia bataticola were predominant. Cultivars NP-69 (late) and Prabhat (extra early) harbored more fungi than did T-21 (early) or ICP-1 (mid). Genotypic differences rather than weather during pod maturity, or different storage periods seem to Influence the intensity or seed-borne mycoflora. Greater reduction in seed germination was observed incultivars NP-69 and Prabhat which had higher frequency of mycoflora, especially Aspergillus spp. Seed treatment with Benlate T at 3 g/kg provided crmplete control of all seed-borne fungi with no adverse effect on germination. This treatment can be recommended for controlling seed-borne mycoflora to ensure safe imernational exchange of seed

Host specificity of pigeonpea wilt pathogen, Fusarium udum.

Of 30 weed spp. collected, 10 yielded F. isolates but none of these was F. udum and none of the spp. tested showed wilt symptoms. None of the 21 crop plants tested in wilt-sick pots and plots developed wilt but leaf drying and defoliation were observed on a few cotton plants in the plots. A pathogenic form of F. udum was isolated from the roots of such plants but these results have not yet been confirmed under field conditions

Studies on the effects of cropping system on fusarium wilt of pigeonpea

Studies on the effects of crop rotation and intercropping on the soil borne wilt [Fusarium udum (Butler)] of pigeonpea were conducted in a wilt-sick plot at ICRISAT Center, India, from 1979 to 1983. The wilt incidence in a continuous sole pigeonpea treatment was 64% in the year 1981 and 80–90% or more in the remaining three years. One-year breaks of sorghum and fallow produced substantial reductions in wilt incidence in the following pigeonpea crop. After two cycles of break crop followed by pigeonpea, wilt incidence was only 16% in the sorghum rotation and 31% in the fallow rotation. Averaged over these two cycles, pigeonpea seed yields were increased from only 93 kg/ha to 340 and 495 kg/ha after the sorghum and fallow breaks, respectively. A break with tobacco caused less reduction in wilt incidence than with other break crops, but pigeonpea yield was increased to 398 kg/ha. A one-year break of cotton or one year of a wilt-resistant line of pigeonpea delayed wilt development, but did not reduce final wilt incidence or significantly afftect yield. Wilt incidence increased again in the second successive pigeonpea crop ater a one-year sorghum break, although it was still significantly less than that in the continuous pigeonpea. After a two-year sorghum break, the effects lasted longer, the wilt incidence being only 24% in the second successive pigeonpea crop. Intercropping with sorghum produced a large reduction in wilt incidence in pigeonpea in the first year (down to 55%) and thereafter it stabilised at about 20–30%. Although intercropped pigeonpea yields were greater than the partial yields normally expected in intercropping, they were no higher than the sole crop yields. The reduced wilt incidence due to a sorghum intercrop was found to be consistent across 14 susceptible pigeonpea genotypes grown in another experiment, but did not occur with maize as the intercop