Pest Faunal Complex their Incidence and Estimation of Losses in maize (Zea mays L.)
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Date
2015
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Publisher
MPUAT, Udaipur
Abstract
The investigation on “Pest faunal complex their incidence and estimation of losses in
maize (Zea mays L.)” was conducted at Agronomy Farm RCA, Udaipur during kharif 2014.
Ten insect pests were recorded at different growth stage of the crop, among these, stem borer,
Chilo partellus (Swinhoe), armyworm, Mythimna separata Walker, maize aphid,
Rhophalosiphum maidis Fitch, cob worm, Helicoverpa armigera (Hubner), grey weevil,
Myllocerus discolour Bohemann and grasshopper, Hieroglyphus nigrorepletus Bolivar were
found to be the major pests of the crop. Among the natural enemies four coccinellid beetles,
green lacewing and Cotesia flavipes Cameron, the larval parasitoid of stem borer were
recorded.
The incidence of stem borer and grey weevil was commenced in second week of
August and the incidence of armyworm, grasshopper and aphid and their natural enemies
(coccinellids and Chrysoperla carnea Stephen) was commenced in third week of August.
While, the incidence of cob worm was commenced in last week of August. The population of
stem borer attained its peak during in first week of September. While, grasshopper and aphid
and their natural enemies (coccinellids and C. carnea) attained its peak during in the second
week of September, while grey weevil, armyworm and cob worm attained its peak during in
the third week of September. The stem borer in terms of leaf injury rating and per cent dead
hearts formation showed a significant positive correlation with morning, evening and mean
relative humidity and total rainfall while, a significant negative correlation with maximum
temperature but non-significant positive correlation with minimum temperature and nonsignificant
negative correlation with mean temperature. The population of grey weevil,
armyworm, aphid and grasshopper did not show any significant correlation with maximum,
minimum and mean temperature, morning, evening and mean relative humidity and total
rainfall. The population of cob worm exhibited significant negative correlation with
minimum temperature but non-significant negative correlation with maximum temperature,
mean temperature and evening and mean relative humidity while, non-significant positive
correlation with morning relative humidity and total rainfall. The population of C. carnea
showed significant positive correlation with morning relative humidity while, maximum,
minimum and mean temperature; evening and mean relative humidity and total rainfall did
not show any significant correlation. The population of coccinellids did not exhibit any
significant correlation with maximum, minimum and mean temperature, morning, evening
and mean relative humidity and total rainfall. The C. carnea and coccinellids population
exhibited a significant positive correlation with the aphid population. The highest parasitism
by C. flavipes on larvae of stem borer was recorded in the first week of September.
The insect pests infestation significantly influenced the yield attributing characters
and maize yield. In unprotected plot, the plant showing leaf injury and plant showing dead
heart was 56.81 and 68.98 per cent, respectively more than protected plots. The reduction in
plant height and grain yield/plant (g) due to insect pests infestation was 5.85 and 26.64 per
cent, respectively. Insect pests caused 14.67q/ha losses in grain yield of the crop which is
equivalent to a loss of 27.38 per cent.
Description
Pest Faunal Complex their Incidence and Estimation of Losses in
maize (Zea mays L.)
Keywords
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Citation
Kumar and Mahla, 2015