EFFECT OF URDBEAN LEAF CRINKLE VIRUS ON BIOCHEMICAL PROPERTIES OF URDBEAN PLANTS IN RELATION TO WHITEFLY AND ENVIRONMENTAL FACTORS.

The urd bean (Vigna mungo (L) Hepper) is an important pulse crop produced worldwide. The Urdbean Leaf Crinkle Virus (ULCV) is a widespread disease of urdbean in Pakistan because it causes extensive damage to its yield. ULCV is infected by two most important pest, whitefly, and beetles. The environmental factors also play a vital role in the spread of disease. Among the environmental factors, the relative humidity and temperature have a significant impact on the ULCV disease. Moreover, the relationship between environmental factors, ULCV and whitefly populations is significant and shows non-remarkable interactions. It has been found that the total chlorophyll of the infected plants has increased on an average of 18.47 (12.3-24.4) which is significantly different from healthy plants. Moreover, the photosynthetic rate of the infected urdbean genotype has also increased on an average of 5.36 (4.36-8.97) compared to healthy plants 2.20 (1.42-2.95). The total phenol in the infected plants after the ULCV infection was 82.19 (74.32- 85.18) milligrams/kg which increased to 102.5 (94.2-111.5) milligrams/kg of fresh weight. In conclusion, the infected plants have higher photosynthetic rate, chlorophyll contents and total phenol content than the healthy plants. All urdbean genotypes were found to be susceptible to ULCV. Furthermore, both environmental factors and whitefly populations have a positive impact on the ULCV disease. [ABSTRACT FROM AUTHOR]