Eco-Toxicological Studies on the Solenopsis Mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Coccoidea: Pseudococcidae) and its Predators
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Title |
Eco-Toxicological Studies on the Solenopsis Mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Coccoidea: Pseudococcidae) and its Predators
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Creator |
SACHIN SURESH SUROSHE
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Contributor |
R. D. Gautam
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Subject |
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Description |
T-8457
There are about 2000 species of mealybug occurring on about 250 plants families throughout the world and in India, more than 100 species of pseudococcids are known to attack a variety of plant species. Solenopsis mealybug, Phenacoccus solenopsis Tinsley, a pest of ornaments and fruit trees worldwide is cryptic in nature. It has already been recorded from 154 plant species belonging to 53 families comprising 20 field and horticultural crops, 45 ornamentals, 64 weeds and 25 bush trees. P. solenopsis has recently emerged as a serious sucking pest of India, attacking important field crops such as cotton, okra, tomato, brinjal, chilli and ornamental plants such as Hibiscus rosa-sinensis, particularly in the cotton growing belts of Punjab, Haryana, Gujarat, Maharashtra and Andhra Pradesh. As this mealybug is thought to be an exotic one and might have got introduced recently, the knowledge about its biology, natural enemy complex and management tactics was scanty in Indian conditions. Against this backdrop, studies were taken up on P. solenopsis. Regarding, studies on survey of natural enemies of P. solenopsis, total of 17 parasitoids, belonging to seven families were found associated with various stages of P. solenopsis collected from Delhi, Maharashtra and Andhra Pradesh during 2007 to 2010. An encyrtid, Aenasius bambawalei, was recorded as a main primary parasitoid of P. solenopsis, which served as primary host of all hyper-parasitoids. Among hyper-parasitoids, Promuscidea unfasciativentris was predominant. Interestingly, Aphanogmus sp. and Anastatus sp. are recorded for the first time on P. solenopsis. Besides, a total of ten predators viz.; eight coccinellids and two chrysopids were observed on P. solenopsis. On a good part not a single hyper-parasitoid is gregarious but solitary; otherwise a successful fortuitous biological control of P. solenopsis, with A. bambawalei, would not be possible. 65 Studies on population dynamics revealed that, Brinjal (var. shyamala) planted on 31st July 2007 recorded highest (33.8 adults) P. solenopsis, in March 2008 and lowest (0.93 adults) in November 2007, mealybugs found positively correlated with temperature. The other variety of Brinjal (var. Vikram) planted on14th July 2008 was found negatively correlated with rainfall. The parasitoid, A. bambawalei, was found negatively correlated with P. solenopsis and P. unfasciativentris. Highest (53.73 adults) population of P. solenopsis was observed during November followed by October (21.13 adults) on sorrel planted in 2007. Highest (91.7 adults) population of P. solenopsis was observed during July followed by June (54.5 adults) on sorrel planted in 2008. Mealybug found positively correlated with temperature in sorrel planted 10.07.2007 and 15.04.2008. Highest number of P. unfasciativentris were recorded in October 2008 (116 adults) on sorrel and observed negatively correlated with mealybugs. Okra planted 26.06.2008, recorded highest (11.08 adults) population of P. solenopsis during October. It was positively correlated with temperature. Highest population of A. bambawalei was observed during October (23 adults), and found positively correlated with temperature and P. unfasciativentris which was highest in November (26 adults). China rose recorded highest (51.82 adults) population of P. solenopsis in July 2008, while lowest (0.06 adults) in October 2008. Mealybug was positively correlated with temperature, relative humidity and rainfall. Result about biology of P. solenopsis showed that males went through 4 nymphal instars as against the 3 in females. The total life cycle for female and male was noticed as 14.06 ± 1.09 & 15.53 ± 0.83 days, respectively. Pre-mating, preovipositional, ovipositional and post ovipositional periods for females were recorded as 2.11 ± 1.26, 7.66 ± 0.70, 10.22 ± 2.68 and 3.77 ± 1.71 days, respectively. Females once mate did not mate again. Reproduction was sexual and ovoviviparous, wherein only mated females laid eggs; unmated females did not lay eggs. Studies showed that P. solenopsis females reproduced sexually and not parthenogenetically, so can easily be manage through biological means, because mealybugs reproducing parthenogenetically multiply exponentially during unfavorable conditions and surpass its natural enemies. |
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Date |
2016-11-05T13:41:26Z
2016-11-05T13:41:26Z 2011 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/84066
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Format |
application/pdf
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Publisher |
IARI,DIVISION OF ENTOMOLOGY
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