EFFECTS OF LATE LEAF SPOT INDUCED BY PHAEIOSARIOPSIS PERSONATA (BERK. & M. A. CURTIS VAN ARX) ON YIELD AND SOME PHYSIOLOGICAL PARAMETERS OF GROUNDNUT (ARACHIS HYPOGAEA L.) VARIETIE
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Date
2018-08-27
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Ahmadu Bello University Zaria
Abstract
In 2016 cropping season, two trials were conducted to evaluate the efficacy of
Funguforce® (mancozeb + carbendazim) in the management of late leaf spot of
groundnut induced by (Phaeiosariopsis personata [Berk. & M. A. Curtis van Arx]) in
Samaru, North – West Nigeria as well as to determine the effect of the disease on yield
and yield parameters of groundnut varieties, and to assess the effect of late leaf spot on
crude protein and chlorophyll contents of groundnut. In the first experiment, five
groundnut varieties (SAMNUT 18, 21, 22, 23 and 25) were subjected to sprayed and
unsprayed treatment of mancozeb + carbendazim at three – week intervals. In the
second experiment, SAMNUT - 14, a variety susceptible to the disease was subjected to
five [plants sprayed weekly (T1), plants sprayed biweekly (T2), plants sprayed every
three weeks (T3), plants sprayed every four weeks (T4) and unsprayed plants (T5)]
different frequencies of fungicide application. The experiments were laid out in a
randomized complete block design (RCBD) with three replications and were established
at the Institute for Agricultural Research (IAR) Samaru, Zaria. The parameters recorded
were stand count at emergence, and at harvest, disease severity at 56, 63, 70, 77, 84, 91,
and 98 days after sowing (DAS) based on 1 – 9 scale, percent defoliation, pod and
haulm yields. Area Under Disease Progress Curve (AUDPC), crude protein content and
chlorophyll content were also computed. Results showed that, application of mancozeb
+ carbendazim at the rate of 2 kg ai/ha on groundnut varieties at three weeks intervals
reduced disease severity by 27.29 %, defoliation by 52.57 % with an increase in pod
yield of 16.89 %, haulm yield (17.94 %) and recorded a decrease in AUDPC by
43.39 % compared to the unsprayed plots. The highest yields were recorded for
SAMNUT 21 and SAMNUT 22 that had lowest values for the disease parameters. Low
yields were recorded in SAMNUT 18 and 25 which also had the highest severity,
percent defoliation and area under disease progress curve.