Potential of tasar silkworm (Antheraea mylitta) excreta as fertilizer on growth, yield and quality of rice

Aim: To investigate the integrated use of chemical fertilizer and potential tasar silkworm (Antheraea mylitta) excreta as fertilizer on the growth, yield and quality of rice.. Methodology: A pot experiment was designed in Completely Randomized Design with four replicates with nine treatments, where Terminalia arjuna leaf litter, tasar silkworm excreta and recommended dose of chemical nitrogen fertilizer at 25%, 50% or 100% alone or in combinations was applied in transplanted rice plants. The observations were recorded for different growth parameters at 30, 60 and 90 days interval, while yield traits were recorded at the time of crop harvest. Results: Leaf litter and tasar silkworm (Antheraea mylitta Drury) excreta on growth, yield and quality of rice revealed that application of 100% recommended dose of nitrogen (RDN) from tasar silkworm excreta recorded significantly higher plant height, panicle length, number of grains panicle-1 and 1000 grain weight at rice harvest. While, chlorophyll index, grain yield, number of effective tillers per hill, biological and protein yield of rice recorded significantly higher in 75% recommended dose of nitrogen through chemical nitrogen fertilizer + 25% recommended dose of nitrogen from tasar silkworm excreta. Nitrogen and protein content of grain recorded statistically higher in 50% recommended dose of nitrogen through inorganic fertilizer + 50% RDN from tasar silkworm excreta. Grain yield was significantly correlated with nitrogen uptake and protein yield, plant height, effective tillers per hill, 1000 grain weight, straw and biological yield. Interpretation: Integrated use of 75% RDN through chemical nitrogen fertilizer with 25% RDN from tasar silkworm excreta is suitable for higher production that may reduce the external input of chemical nitrogen fertilizers and promote zero waste management.

Studies on Genetic Diversity and Population Structure of Tasar Silkworm, Antheraeamylitta.Drury

The populations of Indian tropical Tasar silkworm, Antheraeamylitta Drury, the semi-wild, sericigenous, lepidopteran insect are distributed in eco pockets of various States. These ecoraces vary in geography, topography, ecology, food plant flora and frequency of life cycle in latitudinal and altitudinal gradients. They exhibit diversity in phenotypic, behavioural, physiogenetic and commercial characters. In the present study, the SSR amplification of 7 silkworm strains/ecoraces (16 individuals in each, with seven primers which generated polymorphism) yielded a total of 887 bands, out of which 420 were (47.3 %) polymorphic. Most of the bands were observed within the range 130 to 500 base pairs which is in accordance with the allelic size of the primers taken for studies. The subsequent analysis of its population structure using these alleles revealed the formation of population clusters. The study suggests that these markers could be effectively utilized for identifying the genetic variability among tasar ecoraces.

Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) as natural enemy for wood boring pest, Psiloptera fastuosa F. (Coleoptera: Buprestidae) in tropical tasar

In tasar silkworm culture the stem-boring jewel beetle Psiloptera fastuosa Fabr. (Buprestidae: Coleoptera) is considered as a major pest of tasar plant (Terminalia arjuna, Combretaceae) cultivation. The grubs of P. fastuosa often damage the Arjuna stem by causing dieback. Tyrophagus putrescentiae Schrank (Acari: Acaridae) infested buprestid eggs up to 15% and caused egg mortality up to 9%. The mite predation on the buprestid beetle is reported for the first time. The mite seeps the newly-laid egg-fluids causing the egg mortality suggesting that tasar plant stem-boring pest (P. fastuosa) can be partially controlled by the mite as a natural enemy.