Seasonal occurrence and population fluctuation of Eriophyes prosopidis Saxena, a leaf and inflorescence gall mite of Prosopis cineraria (Khejri) in Rajasthan

Abstract

Seasonal variation in the population of Eriophyes prosopidis Saxena was studied in a young and mature tree stand of P. cineraria in the experimental field during 1999-2000. Minimum percentage infestation (from 6.25 to 8.3%) of gall bearing leaves in mature trees ranged in June whereas maximum percentage ranged from 33.8 to 53.8% during the month of September. Seasonal occurrence and population level of E. prosopidis in young trees revealed that total number of mites and their eggs within galls of these leaflets showed a greater variation in different months. The number of mites in young trees remained fairly high during the period from July to November. The average number of mites during this period was 164.5 mites per ten leaflets with a range from 59.5 to 187.0 mites per ten leaflets. The minimum number of mites (43/ten leaflets) was observed in the first week of May whereas the maximum number of mites (280/ten leaflets) was recorded in the last week of October. In case of both young and mature trees, the minimum and maximum activity of E. prosopidis and its eggs per gall was observed in May and November respectively. Leaf area index had a positive impact on the number of galls on young as well as on mature trees. Similarly, number of galls had a positive correlation on the number of mites and number of eggs on young and mature trees, which in its own turn influenced the number of mites and ultimately the number of eggs within the gall.