Impact of Brushing Schedule on Disease Incidence and Cocoon Characteristics of Tasar Silkworm, Antheraea mylitta D., Saturniidae: Lepidoptera
C. Selvaraj
*
Silkworm Seed Production centre, NSSO, CSB, Dharmapuri, Tamil Nadu, India.
D.M. Bawaskar
Basic Tasar Silkworm Seed Organization, CSB, Bilaspur, Chhattisgarh, India.
B.T. Reddy
Basic Tasar Silkworm Seed Organization, CSB, Bilaspur, Chhattisgarh, India.
T. Selvakumar
Basic Tasar Silkworm Seed Organization, CSB, Bilaspur, Chhattisgarh, India.
S.M. Moorthy
National Silkworm Seed Organization, CSB, Bangalore, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
Tasar silkworm rearing is practiced by tribal population faces heavy crop loss due to unpredictable biotic and abiotic stresses. The experiment was conducted to study the impact of brushing schedule on disease incidence and cocoon characteristics of tasar silkworm. Silkworms were brushed in seven different schedules, information on diseases incidence, cocoon weight, shell weight, cocoon colour and flimsy cocoon percentage was collected. The results of the experiment revealed that brushing schedule significantly (P≤0.05) influences the disease incidence and cocoon characteristics of tasar silkworm. The early and on time brushing schedule B2-24.09.22, B3-29.09.23 and B1-19.09.22 recorded higher incidence of diseases (09.67 to 09.85 % of virosis and 06.65 to 06.85 % bacteriosis), whereas, delayed brushing lots such as B5- 07.10.22, B6-12.10.22 and B7-20.10.22 recorded minimum incidence of diseases (03.90 to 06.90 % of virosis and 02.85 to 05.75 % of bacteriosis). Moreover, cocoon yield recorded maximum (85.00 cocoons per dfls) in delayed brushing B5-07.10.22. However, cocoon quality parameters such as cocoon weight (g), shell weight (g) and shell ratio (%) were slightly reduced in delayed brushing lot B5- 07.10.22 (11.75 g, 1.83 g and 15.93 %), when compared to on time brushing lot B1-19.09.22 (12.15 g, 1.98 g and 16.49 %). Moreover, cocoon colour also differed from whitish gray to dusty gray in delayed brushing lots and also those lots recorded a comparatively higher number of flimsy cocoons (B7-04.82 %). However, cocoon yield was maximum in delayed brushing lots in comparison to on time brushing lots. Therefore, the study concludes that delayed brushing lots does not affect the cocoon yield. However, cocoon quality parameters may decrease slightly.
Keywords: Brushing schedule, disease incidence, cocoon yield, quality parameter