MANAGEMENT OF FRUIT ROT OF Capsicum chinense Jacq.THROUGH BOTANICALS
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Date
2018
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Publisher
AAU, Jorhat
Abstract
Fruit rot of Capsicum chinense Jacq. is one of the most destructive
disease causing severe damage to the fruits in the field and considerable losses during
storage, transit and marketing. The causal fungus of fruit rot of C. chinense was
identified and confirmed as Colletotrichum gloeosporioides (Penz.) Penz & Sacc. in
National Fungal Culture Collection of India, Pune. The investigation aimed at
managing the disease by using few botanicals in vitro and in vivo. Ten botanicals
were selected and extraction was done with cold water, acetone and benzene. The
extracts were evaluated at 20 per cent concentration in vitro for their efficacy against
the pathogen. In these three different method of extraction, three (3) botanicals viz.,
Lawsonia inermis (85.01, 88.14 & 86.12%), Allamanda cathartica (74.94, 80.53 &
75.83%) and Acorus calamus (72.25, 77.18 & 66.67%) giving high inhibition of
mycelial growth were selected from the ten botanical tested. The cold water extract of
these botanicals were further tested against C. gloeosporioides at 5, 10 and 15 per cent
concentration. L. inermis at 15 per cent concentration showed significantly highest
inhibitory effect (80.76%) on the mycelial growth of the pathogen, over the control.
This was followed by 10 per cent concentration of L. inermis (73.60%), 15 per cent
concentration of A. cathertica (70.02%) and. A. calamus (68.90%). Least inhibition
was recorded with 5 per cent concentration of A. calamus (40.94%). These three
botanicals at their most effective concentration (15%) were also evaluated for their
effect in managing the disease in pot culture conditions (in vivo) and were compared
with Captan (0.2%). Captan gives the lowest PDI (percent disease index) (11.12%)
followed by L. inermis (15.56%), A .cathartica (17.41%) and A. calamus (21.85%).
The phytotoxic effect of these botanicals at 5, 10 and 15 per cent concentration (if
any) were tested on 25 days old seedlings of C. chinense. It was observed that the
botanicals did not show any phytotoxic effect at all the concentrations tested. The
active chemical components of the effective botanicals were then evaluated. The
active chemical components of L.inermis was identified as 2-hydroxy 1,4-
napthoquinone (Lawsone), A. cathartica have n-hexadecanoic acid, Hexanoic acid,
ethyl ester, Octanoic acid, decanoic acid and A. calamus as 2,4,5-trimethyoxy-1-
proprenylbenzene (Asarone). The inhibitory effects of the botanicals on the mycelial
growth of C. gloeosporioides and a lower percent disease index of fruit rot in in vivo
condition may be because of the presence of these chemicals.