ISOLATION AND CHARACTERIZATION OF ENTOMOPATHOGENIC ...

3.9 EVALUATION OF DIFFERENT FORMULATIONS AND
STORAGE METHODS
Spores of M. anisopliae (Ma2) and V. lecanii (Vl1) were harvested from sorghum
grains and air dried. The carrier materials initially selected in the present study are given in
the Table 4.
The selected oils and flour were initially sterilized in stabs and sterilizable plastic
covers respectively. Further, inoculum (spore preparation) of M. anisopliae and V. lecanii
were thoroughly mixed with oils and flour along with 0.1 per cent Tween-80 under sterilized
conditions. After mixing, they were sealed and stored at different temperatures viz.,
refrigerated temperature, room temperature, in earthen pot kept on wet sand and deep
freezer.
The number of viable spores per g or per ml of inoculant material were determined at
0, 20, 45, 75, 90, 120 and 150 days intervals after incubation using standard plate count
method on SMAY media. The plates were incubated at 28°C for 7 to 10 days. Three
replications were maintained for each treatment.
Treatment combinations
1. 75 per cent conidia + 25 per cent groundnut oil
2. 50 per cent conidia + 50 per cent groundnut oil
3. 75 per cent conidia + 25 per cent mustard oil
4. 75 per cent conidia + 50 per cent mustard oil
5. 75 per cent conidia + 25 per cent sunflower oil
6. 50 per cent conidia + 50 per cent sunflower oil
7. 75 per cent conidia + 25 per cent wheat oil
8. 75 per cent conidia + 50 per cent wheat oil
9. 75 per cent conidia + 25 per cent sorghum oil
10. 75 per cent conidia + 50 per cent sorghum oil
3.10 FIELD EFFICACY OF Verticillium lecanii AGAINST APHIDS
(Aphis craccivora and Brevicornia brassicae)
Field experiments were conducted during kharif 2001 to evaluate the comparative
performance of the V. lecanii in cowpea ecosystem against aphids (Aphis craccivora) and
cabbage aphid (Brevicornia brassicae). The experiment was conducted at the Main
Agricultural Research Station, Dharwad and the crop was sown on June 20 th in case of
cowpea. The experiment in cabbage ecosystem on aphids (Brevicornia brassicae) was
conducted on farmer’s field of Madihal area of Dharwad and. The crop was sown on 19 th
September 2001. The crop was raised following the recommended agronomic practices in
200 m² blocks. For recording observations on the incidence of the mycopathogen, each
treatment block was divided into four quadrants (replications) in case of cowpea and
cabbage. The treatments were randomized completely and plants were tagged with waxed
labels. Observations on the number of the insect infection were recorded on randomly
selected 10 leaves per plant, a day before, 3, 7 and 14 days after imposing the treatments.
3.11 STATISTICAL ANALYSIS
The data obtained from the laboratory and field experiments were statistically
analysed following standard procedures (Gomez and Gomez, 1984). Percentage values were
transformed to arc sin values while, root transformation (√x + 0.5) was followed for larval or
nymphal counts (both total and mycosed) wherever necessary. The data collected were
subjected to pooled analysis of variance. Means were separated by DMRT.