Eco-frendly management of brinjal fruit and shoot borer, Leucinodes orbonalis Guenee (Lepidoptera: Pyralidae).
M. Sc. Thesis,
Department of Horticulture, IAAS, Rampur, Chitwan, Nepal. pp. 80
field survey, and an experiment were conducted to study eco-friendly management
of brinjal fruit and shoot borer, Leucinodes orbonalis Guenee
(Lepidoptera: Pyralidae). Information was collected from 60 brinjal growers (30
each from Chitwan and Dhading district) using structured questionnaries. Field
experiment was laid out in a randomized complete block design (RCBD) with three
replications and five treatments, such as: i) Physical barrier (nylon net); ii)
shoot clipping weekly; iii) physical barrier + shoot clipping; iv) NPV (100 LE l
ml/lit) + Margoson (0.05 azadirachtin) ( 5 ml/litre) weekly spray; and v)
untreated control. Each plot consisted of 6 m x 5.4 m (32.4 m2) area
with 72 plants (spacing RR 75 cm x PP 60 cm) in each. Field survey revealed that
brinjal occupied an important place in commercial vegetable production due to
its longer harvesting period, higher yield, and off-season marketing potentials.
However, farmers relied on heavy use of pesticides on a schedule application
basis that resulted in build up of insect population mainly, L.
orbonalis, causing higher infestation on crop during summer and rainy
season. Field experiment showed that all treatments except clipping in open
field were significantly different from the untreated control on shoot damage,
fruit infestation by number, fruit infestation by weight, and marketable yield.
The highest marketable fruit yield (10.68+4.30 t/ha) was harvested from
the use of barrier + clipping practices followed by use of barrier alone (10.29+1.80
t/ha), use of NPV + Margosom (6.13+2.1 t/ha), and untreated control (5.35+1.10
t/ha). The marketable yield increment over untreated control was the highest in
barrier + clipping (44%), barrier (40%, and NPV + Margoson (9%), respectively.
Similarly, the highest yield loss reduced by the use of barrier + clipping
(20%), barrier (17%), NPV + Margosom (16%), and clipping (8%). Barrier +
clipping had the lowest shoot damage (0.91+0.57%) followed by barrier
alone (1.33+0.41%) and the shoot damage in other treatments, such as
shoot clipping, untreated control, and NPV + Margosom was 2.31+0.68%,
2.41+0.54% and 3.42+0,81%, respectively. Similarly, fruit
infestation for number, and weight of fruit was the lowest in the use of barrier
+ clipping (15.00+5.7, 14.10+3.5%), followed by use of barrier
(17.10+3.13 and 15.8+4.25%), NPV Margosom (34.51+1.76 and
31.62+2.64%), clipping (38.00+8.73 and 42.00+4.73%)
untreated control (42.30+4.56 and 43.57+8.9%), respectively. The
natural parasitism of L. orbonalis population reached on an average of
23.33% by hymenopterous parasite during May-June. All treatments are
eco-friendly while use of barrier + clipping was the best for farmers practice
in small scale production, especially for off-season production. It also
resulted low fruit damage (13.8%) than farmers practice (15-16%) but it's
recommendation in commercial scale requires further varification under farmers'
field conditions. All eco-friendly practices tested against L. orbonalis
have no ecological hazards like with insecticides; they rather promote
regulation of insect population and natural balance with long term advantage.