Mosaic Infected Plants Research Articles

Alteration of Cellular Nutritional Elements and Nucleic Acids of Papaya Leaves Infected with Seven Symptomatic Isolates of PRSV-P

The diverse nature of shift in the amount of cellular nutritional elements and nucleic acids as affected by the infection of different isolates of Papaya Ring Spot Virus-Papaya strain (PRSV-P) was studied in this experimentation. The symptomatic isolates used in the present study were mild mosaic, mosaic, fern leaf, severe mosaic, vein clearing, leaf distortion and chlorotic leaf spot. Parameters measured to quantify the alteration of cellular components comprised different nutritional cellular elements (C, N, P and K) and nucleic acids (DNA and RNA). In all occasion of measured parameter, the highest alteration was found in leaf distortion. Almost in all cases the lowest effect was determined with the Mild Mosaic infected plants followed by the mosaic, severe mosaic, vein clearing, chlorotic leaf spot, fern leaf and leaf distortion. Infection of seven different symptomatic isolates of PRSV-P created striking and responsive variability in all parameters studied. And the dependency of the cellular nutritional elements and nucleic acid on seven symptomatic variants of PRSV-P was found significantly correlated in respect to the corresponding yield.

Assessment of components in a set of management practices for the wet-season production of vegetable cow pea in Trinidad

SUMMARYExperiments were conducted in association with farmers during 1977, 1978 and 1979 on a River Estate sandy loam at Valsayn and on a Cunupia clay loam at Piarco, Trinidad, to assess the relative importance of components in a set of practices for wetseason production of ‘yellow shell’ pods of ‘blackeye’ type of cow pea (Vigna unguiculata (L.) Walp.). Though the response of the cow pea growth, yield and seed quality characteristics were similar at both locations, crop performance was consistently better at Valsayn and was attributed to more favourable soil conditions and to a lower incidence of pests (mainly Ceratoma beetles), cow pea severe mosaic virus, and weeds. Overall, it was found that pest control was the most important management factor, accounting for a mean yield increase of 144%. The adoption of the improved cultivar, California Blackeye No. 5, increased yield by 77%. Other inputs resulting in significant yield increases were, in order of magnitude, weed control (40%), roguing of mosaic infected plants (37%) and high plant density of 110000 plants/ha (23%). A fertilizer treatment did not significantly increase yield. The results suggest that adoption of the insect control treatment by farmers in their cultivation of an improved cultivar sown at high plant density, the use of herbicide and roguing of mosaic infected plants have practical potential and would be economically justified for the production of high yields and good quality ‘yellow shell’ pods of vegetable cow pea for processing.

Preference of Green Peach Aphids for Virus-Infected Sugar beet Leaves12

In detached-leaf experiments, apterous Myzus persicae (Sulzer) preferred yellows-infected leaves to symptom less, mosaic-infected, or curly-top-infected leaves. However, apterous aphids appeared to move at random to healthy, mosaic-infected, or yellows-infected whole plants. Twice as many alate aphids were found on yellows-infected whole plants 24 hours after release as on healthy or mosaic-infected plants, but no marked differences were found in numbers of alate aphids on healthy, mosaic-infected, and yellows-infected whole plants 48–96 hours after release. In all tests aphids appeared to avoid curly top-infected leaves or plants.