ABSTRACT
Late Leaf Spot (LLS) disease is caused by Phaeoisariopsis personata, a devastating disease that significantly affects groundnut (Arachis hypogaea L.) production worldwide. This research aimed to investigate the disease progress in resistant and susceptible groundnut genotypes under green house conditions with artificial inoculations. The four popularly growing groundnut cultivars in Andhra Pradesh i.e., Kadiri-6 (K6), Dharani, Harithandra and Lepakshi (K-1812) were evaluated in this study. The disease severity scale, percent disease index (PDI), Area under disease progression curve (AUDPC) and the epidemic rate (rate) were estimated by using the linear model. Highest disease severity was observed in K6 (88.19 %) and Dharani (85.19 %) with greater disease progression rate was observed in K6 (0.13) and Dharani (0.12) cultivars. However, the lowest disease progression was observed in Lepakshi (0.04) and Harithandhra (0.08) cultivars. Enhanced resistance to LLS was reported with Harithandhra and Lepakshi cultivars due to slower epidemic rate, longer incubation and latent periods with smaller lesions.
ABSTRACT
The efficacy of four systemic and combination fungicides, namely Carbendazim 12% + Mancozeb 63% WP, Tebuconazole 25% WG, Hexaconazole 4% + Zineb 68% WG, and Tebuconazole 50% + Trifloxystrobin 25% WG, against Rhizoctonia bataticola, the causal agent of dry root rot in groundnut was evaluated using the poison food technique. Among the tested fungicides, Hexaconazole 4% + Zineb 68% WG exhibited the highest efficacy, with 100% inhibition of mycelial growth at all concentrations tested. Tests of compatibility of these fungicides with Trichoderma asperellum revealed that Hexaconazole 4% + Zineb 68% WG caused 38.88% of growth inhibition in T. asperellum while the other fungicides tested were totally incompatible with100 percent inhibition.