Journal of Horticultural Sciences

M. Mani ¹, A. Krishnamoorthy ¹, C. Shivaraju ¹

Affiliations
1 Division of Entomology and Nematology, Indian Institute of Horticultural Research, Bangalore -560 089, IN

Abstract

Mealybugs, known to be 'hard to kill pests', live in protected areas and most stages in their life cycle are covered in a waxy coating. Several insecticides are found ineffective against mealybugs. Fortunately, mealybugs - being sessile insects - are more amenable to biological control. The exotic parasitoid, Leptomastix dactylopii How., was found to be highly effective in suppressing citrus mealybug, Planococcus citri (Risso.) permanantly on citrus, sapota, guava, pomegranate and coffee. This is one of the recent successes in classical biological control attempts in India. However, the Australian ladybird beetle, Cryptolaemus montrouzieri Muls., often provides spectacular control of heavy infestation of P. citri on acid lime, lemon, sweet orange, pummelo, Crossandra and custard apple. Though Anagyrus dactylopii (How.), is a potential parasitoid of pink hibiscus mealybug, Maconellicoccus hirsutus (Green), on grapes, releases of C. montrouzieri only help in suppression of the pink hibiscus mealybug on grapes, ber, guava, sapota, custard apple, citrus and hibiscus. The encyrtid parasitoid, Tetracnemoidea indica (Ayyar), was able to check the oriental mealybug, Planococcus lilacinus (Ckll.) on acid lime and pomegranate. The predators, C. montrouzieri and Spalgis epeus Westwood, also play a major role in suppression of P. lilacinus on guava, ber, sapota and chow-chow. The local parasitoid, A. dactylopii was seen to play a major role in suppression of spherical mealybug, Nipaecoccus viridis (Maskell) on citrus and jackfruit. Nevertheless, releases of C. montrouzieri are found highly effective in controlling N. viridis on acid lime and pummelo. Similarly release of C. montrouzieri is found to be highly effective in controlling striped mealybug, Ferrisia virgata (Ckll.), on guava, tuberose and Acalypha in 30-40 days of release. A local parasitoid, Aenasius advena Comp., also plays a major role in suppression of F. virgata on guava, mango, guava, hibiscus, fig, citrus, etc. Release of the coccinellid predator, C. montrouzieri, was found very effective in controlling the mango coccid, Rastrococcus iceryoides (Green) on mango and also on the medicinal plant Decalepis hamiltonii. The encyrtid, Praleurocerus viridis (Agarwal), was found very effective in reducing populations of R. iceryoides on guava. Spalgis epeus was found to be the predominant predator of the papaya mealybug, Paracoccus marginatus Williams and de Granara Willink, but releases of the exotic parasitoid, Acerophagus papayae (Noyes&Schauff), only provide excellent control of P. marginatus within 3-4 months of release. The second successful classical biological control attempt on mealybugs in India. The brinjal mealybug, Coccidohystrix insolita (Green), is known to attack brinjal, Coleus, Hibiscus, etc. Cryptolaemus montrouzieri effectively controlled mealybugs on these three crops in 30-40 days of release. Verticillium lecanii Zimm. (Phule bugicide @ 2g/L) is found to be effective in killing the mealybug. Other fungal pathogens, viz., Beauveria bassiana (Bals.) Vuill and Metarhizium anisopliae (Metch.), are also seen to infect mealybugs in rainy season under humid conditions.

Keywords

Mealybug, Biocontrol, Classical Biocontrol, Parasitoid, Predator.

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A. Krishnamoorthy ¹, P. N. Ganga Visalakshi ¹, A. Manoj Kumar ², M. Mani ¹

Affiliations
1 Division of Entomology and Nematology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore-560 089, IN
2 Department of Crop Physiology, UAS, GKVK, Bangalore- 560 065, IN

Abstract

An in vitro study was conducted to determine the interaction effect of ten pesticides tested at field recommended dose on conidial germination, vegetative growth and sporulation of Lecanicillium lecanii(ZIMM.) ZARE&GAMS. Compatibility of L. lecanii to different pesticides was found to be varied. Conidial germination was 99.3 and 85.7% in Pongamia oil and acephate, whereas, it was totally inhibited by the presence of chlorothalonil, iprodion + carbendazim, carbendazim and thiophanate methyl indicating that these pesticides were highly toxic. Dinocap recorded as moderately toxic while endosulfan, abamectin and ethion were least toxic based to the germination of conidia. So also Iprodion + carbendazim did not and carbendazim allow L. lecanii to put forth mycelium growth in their presence. Thiophanate methyl, Pongamia oil, acephate, endosulfan, ethion and chlorothalonil were observed to be innocuous pesticides registering growth of mycelium upto 2.33, 2.23, 2.23, 2.03, 2.03 and 2.00 cm dia., respectively, from 0.6 cm dia. held in the center of Petri plate on 14^th day after treatment. As far as sporulation is concerned, Pongamia oil alone recorded the maximum yield of 47.2x10⁶ conidia/ml followed by 18x10⁶ conidia/ml, in chlorothalonil as against 20x10⁶ conidia/ml in control, which means that the pongamia oil exhibited synergistic effect on L. lecanii, yielding more conidial spores. Thus, based on in vitro interaction study, pongamia oil alone was found to be safe to the entamopathogenic fungus L. lecanii in nature and iprodion + carbendazim and carbendazim were found to be highly toxic.

Keywords

Botanicals, Pesticides, Lecanicillium lecanii.

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M. Mani ¹, A. Krishnamoorthy ²

Affiliations
1 National Research Centre for Grapes, P.B. No. 3, Manjari Farm, Solapur Road, Pune - 412 307, IN
2 Division of Entomology and Nematology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore - 560 089, IN

Abstract

The exotic spiralling whitefly, Aleurodicus dispersus Russell, was observed to infest several ornamentals including rose, hibiscus, poinsettia and acalypha in and around Bangalore. Efforts were made to colonize the aphelinid parasitoid, Encarsia guadeloupae Viggiani, during 2002 - 2003 on the above ornamentals infested with the spiralling whitefly. A total of five predators, namely, Axinoscymnus puttarudriahi Kapur and Munshi, Cryptolaemus montrouzieri Muls., Anegleis cardoni (Weise), Mallada astur (Banks) and Cybocephalus sp. were observed on the spiralling whitefly on these ornamentals during the study but their impact on the spiralling whitefly was negligible. Inoculative releases of E. guadeloupae were made on rose (156 adults), hibiscus (179 adults), poinsettia (124 adults) and acalypha (247 adults). Encarsia guadeloupae was recovered within a month after its release with 3.43-32.94% parasitism. A steady decline in the population of spiralling whitefly was observed on these ornamentals. Encarsia guadeloupae was found to be the only parasitoid encountered throughout the study and the total parasitism steadily increased up to 96.00% on rose, 86.40% on hibiscus, 90.40% on poinsettia and 39.86% on acalypha at six months from release. Parasitism by E. guadeloupae was significant and negatively correlated with the population of spiralling whitefly on all the four ornamentals.

Keywords

Aleurodicus dispersus, Encarsia guadeloupae, Biological Control, Spiralling Whitefly, Rose, Hibiscus, Poinsettia, Acalypha.

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M. Mani ¹, A. Krishnamoorthy ²

Affiliations
1 National Research Centre for Grapes, Pune-412307, IN
2 Division of Entomology and Nematology, Indian Institute of Horticultural Research, Bangalore -560 089, IN

Abstract

Severe infestation of green shield scale Chloropulvinaria psidii (Green) was observed during 2003-04 on the medicinal plants namely Withania somnifera, Madhuca longifolia, Mimusops elengi and Wrightia tinctoria. The Australian ladybird beetle Cryptolaemus montrouzieri Mulsant was released @ 20 larvae/plant. Following the release of C. montrouzieri , the scale population declined from 173.48 to 4.35/plant on W. somnifera, 30.49 to 1.20/plant on M. longifolia, 90.20 to 3.57/plant on M. elengi and 240.86 to 4.92/plant on W. tinctoria. There was 89.13 to 97.96% reduction in scale population 45-75 days after release of C. montrouzieri on the above medicinal plants. No other natural enemy, except C. montrouzieri, was recorded on C. psidii. There was no correlation between temperature, relative humidity or rainfall and scale population. Hence, the reduction in population of green shield scale was attributed mainly to the action of C. montrouzieri.

Keywords

Chloropulvinaria psidii, Cryptolaemus montrouzieri, Withania somnifera, Madhuca longifolia, Mimusops elengi, Wrightia tinctoria.

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