The invasive mealybug Phenacoccus solenopsis Tinsley, a threat to tropical and subtropical agricultural and horticultural production systems - a review.

The introduction of Bacillus thuringiensis (Bt) cotton has reduced the burden of pests without harming the environment and human health. However, the efficacy of Bt cotton has decreased due to field-evolved resistance in insect pests over time. In this review, we have discussed various factors that facilitate the evolution of resistance in cotton pests. Currently, different strategies like pyramided cotton expressing two or more distinct Bt toxin genes, refuge strategy, releasing of sterile insects, and gene silencing by RNAi are being used to control insect pests. Pyramided cotton has shown resistance against different cotton pests. The multiple genes pyramiding and silencing (MGPS) approach has been proposed for the management of cotton pests. The genome information of cotton pests is necessary for the development of MGPS-based cotton. The expression cassettes against various essential genes involved in defense, detoxification, digestion, and development of cotton pests will successfully obtain favorable agronomic characters for crop protection and production. The MGPS involves the construction of transformable artificial chromosomes, that can express multiple distinct Bt toxins and RNAi to knockdown various essential target genes to control pests. The evolution of resistance in cotton pests will be delayed or blocked by the synergistic action of high dose of Bt toxins and RNAi as well as compliance of refuge requirement.

/pdf/insect-resistance-management-in-bacillus-thuringiensis-33j39uhtds.pdf

Insect resistance management in Bacillus thuringiensis cotton by MGPS (multiple genes pyramiding and silencing)

A temperature-based phenology model for predicting development, survival and population growth potential of the mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

The pink bollworm Pectinophora gossypiella (Saundars) (Lepidoptera: Gelechidae) has recently emerged as a serious menace on Bt cotton in India. Extensive roving surveys were conducted in 83 locations spread across 16 major cotton growing districts of Maharashtra State, India to assess the level of pink bollworm infestation in Bt cotton. The dynamics and severity of pink bollworm damage during the different stages of boll development (90–130 days of crop age) were assessed based on random sampling of green bolls, opened bolls and picked bolls per plant and number of locules damaged per boll. Survey results revealed a widespread infestation of pink bollworm on Bt cotton across the surveyed sites in a range of 40–95% which accounts for anticipated yield losses between 20 and 30%. A typical pattern of progressive increase in the level of pink bollworm infestation and intensification of locular damage with the advancement of the crop season was observed. The pink bollworm hitherto was supposed to be under control since the introduction of Bt cotton in India, now it appears to be widespread, especially on Bt cotton throughout the cotton growing areas of Maharashtra State which shares approximately 36% and 25% of the country’s cotton area and production, respectively. This article discusses the implications of serious outbreak of pink bollworm infestations in Bt cotton and also suggest measures necessary to mitigate its potential threat to Indian cotton production. The modulation of management practices aimed at manipulation of cotton cropping pattern being followed in the country in general and Maharashtra in particular could strengthen the management of pink bollworm populations effectively. We discuss the practicality of several management options aimed at achieving this goal.

Widespread infestation of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechidae) on Bt cotton in Central India: a new threat and concerns for cotton production

Aenasius bambawalei has been recently reported as a solitary endoparasitoid of Phenacoccus solenopsis in India. Laboratory experiments were conducted comparing the parasitoid's preference for the three developmental stages of mealybug and its effect on parasitism, development, progeny fitness and sex ratio of A. bambawalei. The studies revealed third instar mealybugs as the most preferred stage for development of the parasitoid.

Suitability of various stages of mealybug, Phenacoccus solenopsis (Homoptera: Pseudococcidae) for development and survival of the solitary endoparasitoid, Aenasius bambawalei (Hymenoptera: Encyrtidae)

Mealybug was considered to be a minor pest of cotton but it emerged as a major pest in 2006-2007 in North and Central zones. Extensive field surveys conducted in cotton fields during 2007-09 in Haryana, Rajasthan and Punjab in the North zone and Madhya Pradesh, Maharashtra and Gujarat in the Central zone indicated that Phenacoccus solenopsis was the only major species of mealybug recorded on cotton in North as well as Central zones except one location in Gujarat where Fenrrisia virgata Cockerrel was also recorded. Infestation of mealybug at most of the places in North and Central zones ranged from mild (10-20%) to high (40-60%) during 2007 and 2008 but reduced to traces in 2009. Extensive field survey indicated that Aenasius bambawalei Hayat (Chalcidodea: Encyrtidae), an indigenous parasitoid, played a key role in reducing the insect pestinfestation. The parasitoid was first recorded in Delhi in July 2008 and by 2009 it was found in most of the cotton growing districts of North and Central zones. Its natural parasitization on P solenopsis could reach more than 90% at many locations. This is the most successful example of biological control of mealybug. Along with this parasitoid, another parasitoid, Promuscidea unfasciativentris Girault (Chalcidodea: Aphelinidae), was also recorded at most of the locations in smaller proportions.

Survey for cotton mealybug, Phenacoccus solenopsis (Tinsley) and its natural enemies.

Record of new parasitoids on mealy bug, Phenacoccus solenopsis.

The results of field survey carried out in 14 villages in Sirsa district (Haryana) indicated increasing trend in the population of Spodoptera litura (Fab.) from 1.36±0.96 ((ange 0.30–3.47) in 2004 to 2.43±2.0 (range 0030-7.35) per plant in 2005. The field experrments conducted on natural infestation of Bt and non Bt cotton hybrids revealed that the incidence of S. litura on Bt cotton initiated in 38th and 35th Meteorological Standard Week (MSW) in 2004 and 2005, respectively. The population reached maximum of 1.50 larvae per plant and 0.9 larva per plant in RCH-134 Bt and Ankur 651 Bt on 40th and 38th MSW during 2004 and 2005, respectively. The difference between the incidence of S. litura in Bt cotton (Bollgard I - Cry 1Ac) (0.25–0.28 larva per plant) and non Bt cotton (0.10–0.28 larva per plant) remained statistically non significant.

Spodoptera litura: An Emerging Pest on Bt Cotton (Cry 1Ac) under North Indian Conditions

Solenopsis mealybug, ( Phenacoccus solenopsis ) infests cotton at Perambalur district of Tamil Nadu. During the surveys carried out during 2008-10, coccinellids Scymnus nubilus Mulsant, Hyperaspis maindroni Sicard, green lacewing, spiders, Aenasius bambawalei Hayat, Homalotylus eytelwenii Ratzeburg (Encyrtidae) Promuscidea unfasciativentris Girault and Coccophagus sp. (Aphelinidae) were recorded. The per cent emergence of S. nubilus was highest (68%) during second week of February and lowest (6%) during last week of November. The highest percentage (18%) of H. maindroni was recorded during second week of February and lowest (2%) during third week of March. The highest parasitisation (76%) by A. bambawalei was recorded during last week of February whereas it was lowest (8%) during last week of December. Similarly, the highest parasitisation (28%) by P. unfasciativentris was recorded during third week of February whereas it was lowest (2%) during third week of March. But the percent parasitized mealybug by Coccophagus sp . was very lower than others. A. bambawalei and P. unfasciativentris were most common parasitoids on mealybug P. solenopsis in cotton.

/pdf/predators-and-parasitoids-of-cotton-mealybug-phenacoccus-1kl7y9qxtu.pdf

Predators and parasitoids of cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) in Perambalur district of Tamil Nadu.

Abstract The decline of soil nutrient status and productivity of crops, and restoration of soil health is a key global concern. Crop yields are reduced by soil degradation, which endangers the world's food supply. Crop yields and soil health are further decreased by improper fertilizers use in conjunction with intense cropping. A wide variety of plants, particularly monocotyledonous crops can collect significant levels of silicon in their organs showing the benefits of silicon in terms of growth, biomass, and yield, whereas most dicots are unable to accumulate enough Si under their epidermal system. In the present investigation, treatment of applying silica solubilizer at a rate of 12.5 kg with 50 kg FYM/ha in soil with sett treatment of 0.5% K 2 SiO 3 ,2.5% urea and potash foliar spray in a specified time showed a significant result in all the growth and yield parameters tested when plant and its ratoon were in drought condition. 

/pdf/potential-applications-of-silicate-solubilizing-bacteria-and-sp51r2ag.pdf

Potential Applications of Silicate Solubilizing Bacteria and Potassium Silicate on Sugarcane Crop under Drought Condition

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