STUDIES ON MANAGEMENT OF ANGOUMOIS GRAIN MOTH, Sitotroga cerealella (Oliver) AND LESSER GRAIN BORER, Rhyzopertha dominica (Fab.) IN PADDY DURING STORAGE
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Date
2014
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY
Abstract
The present investigation entitled “Studies on management of Angoumois grain moth, Sitotroga cerealella (Oliver) and Lesser grain borer, Rhyzopertha dominica (Fab.) in paddy during storage” was conducted in the Department of Entomology, Agricultural College, Bapatla, Guntur district, Andhra Pradesh during 2013-14.
A total of 56 released and pre released rice varieties were screened for their susceptibility to S. cerealella and R. dominica. Screening was done based on the following parameters viz., number of moths emerged, mean developmental period and susceptibility index. The varieties were categorized as “least susceptible”, “susceptible” and “highly susceptible” based on susceptibility index values. Three major ruling / popular varieties in Andhra Pradesh were selected from each group based on the susceptibility index values for a detailed study on the bionomics of S. cerealella and R. dominica and analyzed for protein, carbohydrate, amylose and total phenol contents.
Paddy varieties viz., BPT-2689 (PR), JGL-3844, MTU-1031, WGL-3962, JGL-11727, CM-9 (2012), JGL-1798, MTU-1038 (PR), BPT-2618 (PR), JGL1804 and NLR-30491 with less adults emergence, prolonged mean developmental period and lower susceptibility index were categorized as “Least susceptible” varieties to S. cerealella infestation.
Similarly, the paddy varieties viz., MTU-1031, CM-9 (2012), NLR-34449, WGL-3962, NLR-20084, BPT-2689 (PR), JGL-11470, MTU-1075, JGL-11727, JGL-3844, NLR-30491 and JGL-1798 were recorded as “Least susceptible” to R.
dominica infestation. Remaining all the varieties were found to be falling under the category of susceptible and highly susceptible to S. cerealella and R. dominica.
The average number of eggs per female of S. cerealella was 94.76 which ranged from 75.60 to 110.60. The average longevity period of female moths ranged from 5.2 to 6.4 days and that of males from 4.6 to 5.7 days. The average duration of incubation, larval and pupal periods were found to vary from 4.2 to 5.2, 13.6 to 19.4, 5.1 to 7.5 days, respectively on different paddy varieties. Similarly, the average duration of incubation, larval and pupal periods of R. dominica on different paddy varieties ranged from 5.8 to 6.3, 25.0 to 31.1 and 5.3 to 6.6 days, respectively.
The per cent weight loss and per cent damage of paddy varieties due to infestation by S. cerealella were ranged from 0.66 to 8.12 % and 0.39 to 11.18% respectively. Similarly, due to the infestation by R. dominica, per cent weight loss and per cent damage of paddy varieties were ranged from 0.30 to 7.30 % and 0.71 to 10.67 % respectively.
The protein, carbohydrate, amylose and phenol contents of uninfested paddy varieties ranged from 5.86 to 8.56 %, 70.49 to 79.60 %, 20.24 to 35.71 % and 239 to 438 mg/100g, respectively. Significant positive correlation was observed between per cent damage and per cent weight loss due to S. cerealella and R. dominica with regard to protein content of paddy varieties, whereas, negative correlation was observed with regard to phenol content of paddy varieties. The infestation of S. cerealella and R. dominica on paddy varieties showed significant increase in protein and phenol contents after three months period of storage.
The talc formulation of two entomopathogenic fungi viz., B. bassiana and M. anisopliae containing 1 x 109 CFU. g-1 (5 g. kg-1) were used alone and in combination with two different concentrations (750 mg. kg-1 and 1000 mg. kg-1) of Diatomaceous earth (DE) against S. cerealella and R. dominica on paddy (Var. BPT-5204) during storage.
Among the treatments tested after 14 days of exposure, 100 % adults of R. dominica were found dead in paddy treated with higher concentration of DE i.e., 1000mg. kg-1 in combination with B. bassiana and M. anisopliae which are significantly different from other treatments. But in case of S. cerealella there is no significanct difference between the treatments and untreated control. The treatments tested could not cause any significant mortality in the adults of S. cerealella, as they were not in direct contact with the contaminated grains except for the purpose of oviposition by the female adult moths. Thus, significantly less F1 adults were recorded in paddy treated with the higher concentration of DE in combination with B. bassiana (9.33 and s respectively) and M. anisolpliae (11.33 and numbers respectively).
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Keywords
ANGOUMOIS, GRAIN MOTH, Sitotroga cerealella, Oliver, GRAIN BORER, Rhyzopertha dominica, Fab., PADDY
Citation
143P.