Biochemical changes in cotton plants due to infestation by cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

The study on biochemical changes in cotton plants (Gossypium hirsutum L.) due to infestation by cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) was conducted at CICR Nagpur during 2014-15. Total protein contents estimated from the shoots of the healthy plants (4.29 mg/g) indicated 50.5% increase over the healthy plants (2.85 mg/g). Total phenol content increased by 185.7% in the mealybug infested plants (0.20?g/g) over the healthy plants (0.07?g/g). Insignificant difference in the level of total soluble sugar was observed in mealybug infested plants (1.00?g/g) as compared to healthy plants (0.90?g/g). Total reducing sugar was found to be unaffected with the mealybug infestation. Although there was depletion in all the photosynthetic pigments viz., chlorophyll a (19.1%), chlorophyll b (23.7%), total chlorophyll (21.2%) and carotenoids (20.8%) due to the mealybug infestation, these values were not statistically different in the healthy plants. This is the first report on biochemical changes in cotton plant due to infestation of P. solenopsis

Relative toxicity of insecticides against cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera:Pseudococcidae) and its fortuous parasitod Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae)

Nineteen insecticidal formulations from 10 groups of insecticides were evaluated for their relative toxicity against cotton mealybug Phenacoccus solenopsis Tinsley and its fortuous parasitoid Aenasius bambawalei Hayat. Insects were exposed to cotton leaves dipped in insecticidal solutions and their mortality was recorded at 24-h intervals. Within 24 h of exposure, Quinalphos, Chlorpyriphos, Thiamethoxam and Profenophos have detrimental effect on both P. solenospis and A. bambawalei recorded more than 70% mortality. Thiodicarb was extremely toxic to P. solenopsis and least toxic to A. bambawalei where as Spinosad was less toxic to P. solenopsis and extremely toxic to A. bambawalei. Profenophos, Thiamethoxam and Chlorpyriphos results into > 90% mortality of P. solenospsis while 100% kill of A. bambawalei with Spinosad, Acephate and Chlorpyriphos up to 48 hours. More than 80% mortality of P. solenopsis with Chlorpyriphos, Profenophos, Monocrotophos, Thiamethoxam, Spinosad and of A. bambawalei with Profenophos, Monocrotophos, Flonicamid, Buprofezin, Imidacloprid, Thiamethoxam, Chlorantraniliprole, Flonicamid and Indoxacarb recorded 72 hours after exposure. While at 96 hours, cent per cent mortality of P. solenopsis was recorded with Monocrotophos which was equivalent to Acephate and Spinosad. Least LT50 values were found with Thiodicarb, Quinalphos and Thiamethoxam for P. solenopsis and higher in case of Thiodicarb for A. bambawalei. Spinosad, Chlorpyriphos and Quinalphos were found to be extremely toxic to A. bambawalei. Among the tested insecticides Thiodicarb was found effective against P. solenopsis and relatively safer to A. bambawalei may be used judiciously to manage P. solenopsis that have least implications on the environment

Suppression of Jasmonic Acid-Dependent Defense in Cotton Plant by the Mealybug Phenacoccus solenopsis

The solenopsis mealybug, Phenacoccus solenopsis, has been recently recognized as an aggressively invasive pest in China, and is now becoming a serious threat to the cotton industry in the country. Thus, it is necessary to investigate the molecular mechanisms employed by cotton for defending against P. solenopsis before the pest populations reach epidemic levels. Here, we examined the effects of exogenous jasmonic acid (JA), salicylic acid (SA), and herbivory treatments on feeding behavior and on development of female P. solenopsis. Further, we compared the volatile emissions of cotton plants upon JA, SA, and herbivory treatments, as well as the time-related changes in gossypol production and defense-related genes. Female adult P. solenopsis were repelled by leaves from JA-treated plant, but were not repelled by leaves from SA-treated plants. In contrast, females were attracted by leaves from plants pre-infested by P. solenopsis. The diverse feeding responses by P. solenopsis were due to the difference in volatile emission of plants from different treatments. Furthermore, we show that JA-treated plants slowed P. solenopsis development, but plants pre-infested by P. solenopsis accelerated its development. We also show that P. solenopsis feeding inhibited the JA-regulated gossypol production, and prevented the induction of JA-related genes. We conclude that P. solenopsis is able to prevent the activation of JA-dependent defenses associated with basal resistance to mealybugs

Cotton Plant Health

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Cotton Crop Protection Strategies 2018

uploaded by Dr. M. Sabeshcotton crop protection strategies for the year 201

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Degree day-based model predicts pink bollworm phenology across geographical locations of subtropics and semi-arid tropics of India

Abstract There is a global concern about the effects of climate change driven shifts in species phenology on crop pests. Using geographically and temporally extensive data set of moth trap catches and temperatures across the cotton growing states of India, we predicted the phenology of cotton pink bollworm Pectinophora gossypiella (Saunders). Our approach was centered on growing degree days (GDD), a measure of thermal accumulation that provides a mechanistic link between climate change and species’ phenology. The phenology change was predicted by calculating absolute error associated with DD and ordinal date, an alternative predictor of phenology, for peak moth abundance. Our results show that GDD outperformed the ordinal dates in predicting peak moth abundance in 6 out of 10 selected locations. Using established thresholds of 13.0/34.0 °C, mean DD accumulated between the consecutive moth peaks across different years were estimated at 504.05 ± 4.84. Seven generations were determined for pink bollworm in a cropping season, the length of which varied between 35 and 73 days in response to temperature. Pink bollworm population reached its peak during third generation which can be the target for management actions. The study provides essential information for developing pink bollworm management strategies under climate change

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Not AvailableA new pest, mealybug which was hitherto not familiar earlier started destroying cotton crops caused economic damage, reducing yields up to 40-50% in affected fields since 2006. Several parts of Gujarat which are located on the border of Pakistan which had recent history of mealybugs infestation was severely affected. Mealybug infestation were recorded (Dhara Jothi et al., 2008) in 2006 on G. hirsutum in all the nine cotton-growing states of India, Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh, Maharashtra, Tamil Nadu, Andhra Pradesh and Karnataka. Severe economic damage to G. hirsutum was reported in 2007 (Dhara Jothi et al., 2008) in four major cotton-growing districts (Bathinda, Muktsar, Faridkot and Ferozepur) of Punjab, two districts (Hisar and Sirsa) of Haryana, and low to moderate damage in parts of Maharashtra, Tamil Nadu and Andhra Pradesh. According to Goswami (2007), nearly 2000 acres of cotton crops were destroyed by the mealybug by mid-July and over 100 acres of mealybug-infested Bt cotton was uprooted in Raike-Kalan village in Bathinda. By the end of the Kharif season (June–October), the total damage in 2007 was estimated to range from US$400,000 to 500,000 in north India alone.NAI