screening elite genotypes and ipm of defoliators in groundnut

1. JL-24 (Susceptible check)
2. ICGV-86699 Red
3. GPBD- 5
4. ICGV-86699 Tan
5. GPBD- 6
6. Mutant III
7. GPBD-4, which were replicated trice.
The cut end of the fresh groundnut leaves were covered with wet cotton wad for
maintaining freshness of the leaves. The open top of the tray was covered by muslin cloth
secured with rubber band. Fresh leaves were provided daily morning after cleaning the tray.
Once the larvae attain third instar, only 25 larvae were maintained on each genotype.
Before pupation, larvae were transferred to another tray containing sterilized sawdust. Two
pairs of male and female pupae were kept for moth emergence in cages (35 × 25 × 45 cm) to
study the oviposition period and fecundity. Diluted honey (10%) was provided as adult food in
small vials with cotton wad. Groundnut plants placed in conical flask with water were kept
inside the cage for egg laying. The following parameters were recorded.
Number of days required for completion for each larval instar, prepupa and pupa and
also larval weight, larval mortality at 5, 10 and 15 days after hatching. Per cent pupal survival
on each variety and pupal weight were recorded. Pre-oviposition, oviposition and post-
oviposition period, adult longevity, per cent adult emergence and total life cycle were
recorded.
3.2 IPM modules for Northern transitional zone of Karnataka
3.2.1 Mass multiplication of Nomuraea rileyi
The number of spores per ml was calculated using the following formula. For field
studies the entomopathogenic fungus N. rileyi was cultured on Sabouraud’s Maltose Agar
Yeast (SMAY) medium. For this, 200ml of the medium was put into conical flasks (500 ml),
autoclaved at 15 PSI for 20 minutes, cooled and inoculated with pure culture of the fungus
maintained in culture slants. Inoculated flasks were incubated at room temperature of 26 ± 1 °
C for 15 days. All the steps were carried out in aseptic conditions to avoid contamination.
Spores were harvested with the help of a small sterile metal spatula and stored in small
airtight screw type tubes at 10 ° C and 60 per cent relative humidity.
The suspension of week old spores was made using distilled water and filtered
through muslin cloth. Few drops of Tween-80, a wetting agent was added to the filtrate. From
the stock solution, serial dilutions were made to obtain the required concentration.
Spore count was made using Neaubuar’s haemocytometer
Number of spores per unit = N × 400 × 1000 × 10 × D
Where,
N : Mean number of spores per small square of the haemocytometer.
D : Dilution factor