Agriculture Reference
In-Depth Information
influence the pest build-up, of which, temperature and relative humidity
have been reported to play a significant role.
Studies on the relationship between weather parameters and the popu-
lation dynamics of TMB on cashew indicated that minimum temperature
is negatively correlated with the pest incidence (Godse et al.
,
2005). The
build-up of pest population commenced with the emergence of new flush
during October after the cessation of monsoon shower and the pest re-
mained in the field until January. The major outbreak was reported in No-
vember, coinciding with the emergence of panicles, reaching the peak in
December. The minimum temperature plays a major role in the incidence
of pest population. The favorable minimum temperature for TMB inci-
dence ranged between 13 and 18 °C. Low temperature (12 °C) is antago-
nistic for pest build-up (Table 6.9) (Prasada Rao, 2002).
TABLE 6.9
Effect of Minimum Temperature on Pest Population of TMB
Night surface air temperature (
0
C)
Intensity of TMB
14 to 18
Moderate to severe
12 to 14
Low to moderate
10 to 12
Low
<10
Nil
Fungal pathogens,
viz., Colletotrichum gleosporoides
and
Gleospo-
rium mangiferae
have been reported to cause drying up of young shoots,
inflorescence and immature nuts in cashew. The incidence of this disease
is being reported from different new locations in which it was not preva-
lent earlier. High RH in forenoon during December-February both in 1997
and 1998 and the minimum temperature of 18-20 °C were found to be fa-
vorable for sporulation by fungi. A significant increase in dewfall was one
of the most important factors, which favored the growth, sporulation and
spread of fungi. Cloudiness leading to low bright sunshine hours (2 h/day)
followed by dewfall triggered the growth, sporulation and spread of fungal
pathogens causing inflorescence blight during 1998-1999 in Kannur and
Kasaragod districts (Prasada Rao, 2002).
Seasonal incidence of cashew pest complex with weather parameters
in Andhra Pradesh revealed that the incidence of shoot and blossom web-
