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BIOLOGY, SEASONAL INCIDENCE AND MANAGEMENT OF RED SPIDER MITE, Tetranychus urticae KOCH IN OKRA

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Title BIOLOGY, SEASONAL INCIDENCE AND MANAGEMENT OF RED SPIDER MITE, Tetranychus urticae KOCH IN OKRA
 
Creator SIDDHAPARA MUKESH RAMJIBHAI
 
Contributor Virani V. R.
 
Subject MILLET
AGRICULTURAL ENTOMOLOGY
 
Description Key words: Acaricides, biology, bio-efficacy, okra, seasonal incidence Tetranychus urticae and varietal screening
An investigations were carried out on biology and management of okra red spider mite, T. urticae at Junagadh Agricultural University, Junagadh, Gujarat during 2013-14.
Studies on biology of red spider mite, T. urticae revealed that both the sexes passed through five stages viz., egg, larva, protonymph, deutonymph and adult with a short resting period known as quiescent. The eggs were laid singly, mostly on the lower surface of leaves. The eggs were smooth, soft, round and translucent white. The incubation period was 3.37 ± 1.07 days with 91.06 ± 3.84 per cent eggs hatching. The average larval, nymphochrysalis, protonymphal, deutochrysalis and deutonymphal periods were 1.78 ± 0.58 and 2.67 ± 0.66, 0.65 ± 0.36 and 0.70 ± 0.34, 2.44 ± 0.57 and 2.83 ± 0.75, 0.74 ± 0.42 and 0.96 ± 0.42, 2.20 ± 0.77 and 2.70 ± 0.88 days for male and female, respectively. The matured deutonymph remained in quiescent stage (teliochrysalis) for 0.80 ± 0.27 days in female. This stage was only found in female T. urticae whereas in case of male it was absent. The total developmental period was longer in female (10.66 ± 1.28 days) as compared to male (7.81 ± 1.40 days). The average pre oviposition, oviposition and post oviposition periods were 3.00 ± 1.56 and 1.80 ± 1.13, 5.55 ± 1.61 and 8.37 ± 1.22, 2.30 ± 1.08 and 3.23 ± 1.04 days in unmated and mated females, respectively. The fecundity for unmated and mated female was 26.15 ± 7.74 and 78.37 ± 13.26 eggs. The male lived shorter (10.10 ± 1.65 days) than the mated (13.40 ± 1.92 days) and unmated (10.85 ± 2.54 days) females. The total life period occupied by T. urticae 17.91 ± 2.55 days in male and 24.06 ± 2.14 days in female.
Seasonal incidence of T. urticae revealed that the mite population observed from 2nd week of July to throughout crop life. The higher mite population was noticed during 2nd week of August to 2nd week of October with peak during month of September, 2013 and October, 2014. The mite activity was declined when last picking was completed. Predatory mites and predatory beetle activity were started from 4th and 5th week of July. Wind speed had highly significant negative correlation while, minimum temperature, morning, evening and mean relative humidity and vapour pressure had negative correlation with mite population during kharif 2013-14.
The activity of natural enemies and mite population during kharif 2013 and 2014 showed positive association among them in okra ecosystem. Mite population showed highly significant positive association with Stethorus sp. and predatory mites. While the association between Stethorus sp. and predatory mites were highly significant positive correlation.
On the basis of mite incidence, categorization and yield of okra fruits, cultivar GAO-5 emerged out as highly resistant to T. urticae. Cultivars Arka anamika, GO-2, Arka abhay, GJO-3 and JOL-10-18 were found resistant, whereas JOL-5S-3, Pusa sawani and JOL-1 were susceptible. In contrast to this, Parbhani kranti was recorded as highly susceptible cultivar.
Among the various acaricidal treatments abamectin 0.0025 per cent was significant over rest of treatments by registering highest (91.47%) mortality and fruit yield (8274 kg/ha) and it was at par with fenazaquin 0.01 per cent and propergite 0.05 per cent. The treatments of spiromesifen 0.04 per cent, chlorfenapyr 0.02 per cent and fenpyroximate 0.0025 per cent were found moderate effective in controlling mite. The treatment of dicofol 0.05 per cent, diafenthiuron 0.055 per cent and sulphur 0.20 per cent found less effective against okra mite.
The treatment of abamectin 0.0025 per cent (1: 5.08) was costly but gave effective control of T. urticae in field conditions, whereas propergite 0.05 per cent was proved best treatment with higher net CBR (1: 15.15) followed by fenpyroximate 0.0025 per cent (1: 12.41).
Okra red spider mite, T. urticae passed through five stages viz., egg, larva, protonymph, deutonymph and adult. The peak mite population was noticed during month of September, 2013 and October, 2014. Mite population showed highly significant positive association with Stethorus sp. and predatory mites. Okra cultivar GAO-5 emerged out as highly resistant to T. urticae while Parbhani kranti was recorded as highly susceptible. Propergite 0.05 per cent was proved best treatment with higher net CBR.
 
Date 2016-09-28T17:22:18Z
2016-09-28T17:22:18Z
2015-06
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/79387
 
Language en
 
Format application/pdf