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R. Nisha ¹, J. S. Kennedy ¹

Affiliations
1 Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore, T.N., IN

Abstract

Development and parasitic potential of Acerophagus papayae Noyes on the papaya mealybug, Paracoccus marginatus Williams and Granara de Willink from different host plants like papaya, cotton, mulberry, tapioca, brinjal and hibiscus were studied. The development time of parasitoid, A. papayae in the current study was shortest in mealybugs reared from papaya (10.9 days), followed by cotton (11.8 days), mulberry (12.4 days), brinjal (13.1 days), hibiscus (14.1 days) and recorded 16.3 days of development in tapioca reared papaya mealybug. The parasitisation rate was found to be highest in second instar than third instar and adult female mealybugs from host crop papaya viz., 87.5 per cent followed by cotton (84.2 %), mulberry (80.8 %), brinjal (80.0 %) and potato sprouts (75.8 %) and recorded lowest parasitisation rate in tapioca (67.5%). The parasitization level of parasitoid, A. papayae was maximum in papaya and minimum in tapioca due to the host plant induced changes in the mealybug. The development time was inversely correlated with the parasitic potential and so there was a trade-off between the development and parasitic potential of parasitoid.

Keywords

Fitness Trade-offs, Parasitoid, Acerophagus papayae, Papaya Mealybug, Paracoccus marginatus

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B. Chittappa ¹, R. Nisha ², C. Nickhil ²

Affiliations
1 Department of Agricultural Engineering, College of Agriculture, BENGALURU (KARNATAKA), IN
2 Department of Agricultural Engineering, College of Agriculture, BENGALURU (KARNATAKA), IN

Abstract

The interculturing operation breaks the upper surface of the soil, upischolar_maining the weeds, aerating the soil, making good mulch, so moisture inside properly retained from evaporation. In the animal-drawn hoe, the implement draft and the capacity of the animals to provide the required power will also affect performance, as will ergonomic considerations related to the comfort of the operator. A intercultural hoe could be easily handled, light, strong, durable, cheap, adjustable for different crops and can be easily manufactured locally. The present bullock hoe consists occupied the space coverage of width 95 cm, total height of 102 cm, three number of tynes and angle 41°. The shape of blade is rectangular and beam length of 236 cm. The field capacity of the implement was noted to be 0.27 hectares per hour which included the turning losses, the field capacity was found to be 0.17 hectares per hour for the area of 10×20 m², which gives the field efficiency of 81.43 per cent.

Keywords

Field, Implement, Hoe, Bullock, Blade.

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R. Nisha ¹, J. S. Kennedy ²

Affiliations
1 Department of Crop Protection, Imayam Institute of Agriculture and Technology, Trichy – 621 206, Tamil Nadu, IN
2 Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore - 641 003, Tamil Nadu, IN

Abstract

The bioecology study of any parasitoid using alternative hosts imposes divergent selection pressures on parasitoid populations. In this study, we investigated the bioecology potential of parasitoid Acerophagus papayae Noyes and Schauff on papaya mealybug Paracoccus marginatus Williams and Granara De Willink from different plant hosts. The parameters studied were adult longevity (survival of progeny), fecundity and productivity of female mealybugs and sex ratio of progenies of P. marginatus. The results showed significant differences in bioecology of parasitoid on their natal host (P. marginatus from papaya) compared with the non-natal hosts (P. marginatus from non papaya hosts). It is also compared with honey concentration solution and potato sprouts. The parasitoid is well adapted to the natal host that is papaya compared to others host. However, parasitoids showed a similar high fitness on both natal and non natal hosts. This results could be used to increase the effectiveness of biological control programme on different views.

Keywords

Acerophagus papayae, Paracoccus marginatus, native hosts, non native hosts, biology

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R. Nisha ¹, D. S. Rajavel ²

Affiliations
1 Department of Crop Protection, Imayam Institute of Agriculture and Technology, Kannanur, Thuraiyur, Trichy (T.N.), IN
2 Department of Agricultural Entomology, Agricultural College and Research Institute, Killikulam, Tuticorin (T.N.), IN

Abstract

Tomatine is a glycoalkaloid found in the stems and leaves of tomato plants, which has fungicidal properties. This laboratory studies were carried out to find out the efficacy of tomatine on the Termitomyces fungus found in the termitaria of O. wallonensis, it was applied through Difco media for fungal growth. The overall period of observations (15 days) revealed that tomatine 1000 ppm effectively reduced the mean diameter growth of fungus (1.41 cm) followed by tomatine 900 ppm (1.52 cm). The fungal growth of fungus in the standard check carbendazim 500 ppm was 1.32 cm whereas it was 8.17 cm in untreated check. The highest suppression of fungus was noticed in carbendazim 500 ppm (84.59 %) which was on par with tomatine 1000 ppm (83.44 %). Tomatine 900 ppm was also suppressed the fungus effectively at 82.08 per cent. The least mean per cent suppression (68.37 %) was noticed in the lower concentration of tomatine 600 ppm. The per cent suppression of fungal growth was decreased from 5^th day to 15^th day of observation. This study was supported by many earlier contributions. Finally the result was concluded that tomatine could be used as a termiticide to control fungus growing termites.

Keywords

Tomatine, Subterranean Termites, Termitaria, Termitomyces.

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R. Nisha ¹, D. S. Rajavel ²

Affiliations
1 Department of Crop Protection, Imayam Institute of Agriculture and Technology, Kannanur, Thuraiyur, Trichy (T.N.), IN
2 Department of Agricultural Entomology, Agricultural College and Research Institute, Killikulam, Tuticorin (T.N.), IN

Abstract

A secondary alkaloid, tomatine was extracted from unripen fruits and leaves of tomato. It is a potent antifungal and insecticidal compound that interacts with sterols in the membranes of the insects and shows efficacy against insects and many species of termites. In this research, investigations were carried out to study the antifeedant and repellent activity of tomatine against the termite species Odontotermes wallonensis Wasmann. The result concluded that lowest consumption of food by O. wallonensis workers was recorded in Azadirachtin 100 ppm (0.15 g) followed by Tomatine 250 ppm (0.60 g). Soldiers and nymphs of O.wallonensis consumed 0.54g and 0.56g food in tomatine 250 ppm treatment whereas in treated check (Azadirachtin 100 ppm) consumed 0.14g in both castes as compared to untreated check (1.33 and 1.46 g). And also exhibited the highest repellent activity towards termites at all the doses. Tomatine 1000 ppm caused 82.13, 73.41 and 88.67 per cent repellent activity whereas Azadirachtin 100 ppm caused 88.67, 78.96 and 92.00 per cent in O. wallonensis workers, soldiers and nymphs, respectively.

Keywords

Tomatine, Secondary Alkaloid, Termites, Azadirachtin, Repellent Activity.

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