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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
Ph D
 
Creator SACHIN SURESH SUROSHE
 
Contributor R. D. Gautam
 
Subject Unable to Generate Tags ilovepdf_merged (6).pdf
 
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.
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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.
 
Date 2016-11-05T13:41:26Z
2016-11-05T13:41:26Z
2011
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/84066
 
Format application/pdf
 
Publisher IARI,DIVISION OF ENTOMOLOGY