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Kalamesh Basarigid , K. Karuna ¹, Y. G. Shadakshari ¹, K. S. Jagadish ¹, K. N. Geetha ¹

Affiliations
1 A.I.C.R.P. on Sunflower, Zonal Agricultural Research Station, University of Agricultural Sciences, Bengaluru Karnataka, IN

Abstract

Sunflower is an important oilseed crop of India. The crop is known to suffer from many diseases among which Alternaria leaf blight is one of the most important diseases. Alternaria helianthi was isolated from the leaf samples collected during Kharif. The toxin produced by Alternaria helianthi in potato dextrose broth was purified and based on its carbohydrate and protein content, the toxin was identified as glycoprotein. Toxin at 100 ppm concentration didn't affect seed germination while toxin concentration of 200 ppm to 3000 ppm affected seed germination. Minimum seed germination of 24.66 per cent was recorded when seeds were treated with toxin @ 3000 ppm. Minimum length of sunflower shoots (2.53 mm) and ischolar_main length (2.15 mm) was observed at 3000 ppm. Sunflower seedlings placed in 100 ppm toxin showed curling of leaves and wilting after 24 hr. whereas at 3000 ppm seedlings showed curling of leaves in 5 h and wilted within 12 hr. In detached leaf assay, 100 ppm toxin didn't produce any symptom. However, at concentrations of 500, 1000, 2000 and 3000 ppm, the toxin produced typical necrotic spots without yellow halo on sunflower leaves.

Keywords

Bioassay, Toxin, alternaria Helianthi, Leaf Blight, Sunflower

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Kalamesh Basarigid ¹, K. Karuna , K. S. Jagadish ¹, Y. G. Shadakshari ¹, K. N. Geetha ¹

Affiliations
1 Zonal Agricltural Research Station, University of Agricultural Sciences, Bengaluru Kanataka, IN

Abstract

Symptoms of Alternaria leaf spot/blight were observed in the form of small scattered brown spots on the leaf surface. Further, these spots covered larger leaf area with dark brown margin and yellow halo with indistinct zonations. Linear necrotic lesions were observed on the stem, petioles, capitulum, sepals, and petals at different stages of plant growth. Isolation of the fungus from the infected leaf sample collected from the field yielded Alternaria helianthi and pathogenicity was proved on KBSH 44 which expressed the symptoms in 8-9 days after inoculation under laboratory condition. The pathogenicity studies showed the external symptoms as small scattered brown spots on the leaf surface. Later, these spots increased in size covering larger area with dark brown margin and yellow halo with indistinct zonations. Linear necrotic lesions also appeared on stems, petioles and sepals. Cultural studies revealed that potato dextrose agar (82.80 mm) was the best followed by Sunflower leaf extract agar (71.54 mm) and Richard's agar (63.64 mm) for growth of fungus. Whereas, the growth of A. helianthi was not observed in water agar. In case of liquid media, potato dextrose broth yielded maximum dry mycelial weight (282.79 mg) followed by sunflower leaf extract broth (241.51 mg).

Keywords

Leaf Blight, Symptoms, Isolation, Pathogenecity, Culture Media

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T. D. Nidheesh ¹, A. N. Shylesha ², A. H. Jayappa ¹, K. S. Jagadish ³, Kuldeep Sharma ⁴

Affiliations
1 Department of Agricultural Entomology, College of Agriculture, University of Agricultural Sciences, GKVK, Bengaluru - 560065, Karnataka, IN
2 ICAR-National Bureau of Agricultural Insect Resources, Hebbal, Bengaluru - 560024, Karnataka, IN
3 Department of Apiculture, College of Agriculture, University of Agricultural Sciences, GKVK, Bengaluru - 560065, Karnataka, IN
4 Department of Entomology, Maharana Pratap University of Agriculture and Technology, Udaipur - 313001, Rajasthan, IN

Abstract

The present experiment was aimed at safety evaluation of different insecticides to Cryptolaemus montrouzieri Mulsant, a major predator of mealybugs. In order to understand the impact of chemical insecticides on this predator, different bioassays were carried out. The results of the study showed that the Percent mortality of C. montrouzieri at 24 HAT was highest in profenophos 50% EC (49.33%) followed by thiamethoxam (36.00%) and dinotefuran (30.67%). However, azadirachtin, buprofezin and pymetrozine were found comparatively safer insecticide to C. montrouzieri. Therefore, both of these insecticides, need to be evaluated further under different agro-climatic zones to confirm their suitability, for mealybug management in cotton ecosystem without adversely affecting the performance of C. montrouzieri.

Keywords

Azadirachtin, Bioassay, Buprofezin, Dinotefuran, Phenacoccuss Solenopsis, Profenophos, Pymetrozine, Thiamethoxa.

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A. Sravika ¹, A. N. Shylesha ², K. S. Jagadish ¹, T. M. Shivalingaswamy ³, N. Nagaraju ⁴, M. S. Sheshshayee ⁵

Affiliations
1 Department of Agricultural Entomology, UAS, Bengaluru – 560065, Karnataka, IN
2 Division of Germplasm Conservation and Utilization, ICAR-NBAIR, Hebbal, Bengaluru – 560024, Karnataka, IN
3 Division of Germplasm Conservation and Utilization, ICAR-NBAIR, Hebbal, Bengaluru –560024, Karnataka, IN
4 Department of Plant Pathology, UAS, Bengaluru – 560065, Karnataka, IN
5 Department of Crop Physiology, UAS, Bengaluru – 560065, Karnataka, IN

Abstract

Eocanthecona furcellata (Wolff) is a potential native predator of lepidopteran larvae that can be easily reared under laboratory conditions and released in augmentative biocontrol for management of pests in various crops. For successful mass production of any predator cannibalism under crowded rearing conditions is the major limiting factor. In the present study, attempts were made to know the ideal population considered for group rearing with minimal or no cannibalism. It was recorded that the predator population of 5 to 25 on Corcyra cephalonica (S.) and Galleria mellonella L. and 5 to 30 on Samia cynthia ricini Boisd. and Spodoptera litura F. was feasible for group rearing with higher percent survival rate when reared in different group arenas. The survival percent was higher on hosts, C. cephalonica, G. mellonella, S. litura and recorded lower on S. cynthia ricini under group rearing condition.

Keywords

Corcyra cephalonica, Eocanthecona furcellata, Galleria mellonella, Group Rearing, Optimum Density, Samia cynthia ricini, Spodoptera litura

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Devaramane Raghavendra ¹, K. S. Jagadish ², K. M. Srinivasa Reddy ²

Affiliations
1 ICAR-National Research Centre for Integrated Pest Management, New Delhi 110012, IN
2 Department of Agricultural Entomology, University of Agricultural Sciences, GKVK Campus, Bengaluru 560065, Karnataka, IN

Abstract

Field study was conducted with ecofriendly insecticides on their effects on the foraging activity and time spent of bee pollinators in sunflower during 2016-17 and 2017-18 at the University of Agricultural Sciences, Bengaluru. Significantly less number of bees were observed with mahua oil one day after spray- 2.15 (Apis dorsata), 1.33 (A. cerana), 1.72 (A. florea) and 1.24 (Tetragonula iridipennis). BIPM (biointensive integrated pest management) and spinosad treatments led to maximum number of bees at 4 and 7 days after spray. The least mean time spent was observed with mahua oil treatment, whereas, BIPM and spinosad led to maximum mean time spent for all the bee pollinators. It is concluded that mahua oil has repellent activity on the bee pollinators.

Keywords

Apis spp., Tetragonula iridipennis, sunflower, BIPM, spinosad, mahua oil, foraging activity, time spent

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