 |
| An overall view of the trial plot |
1. Background
Vegetable production during
summer in the cooler regions and during
winter in the warmer belts of the country is a sole activity contributing to
the livelihood of many dwelling in farming community. Among many, the most important cash crop is
cole crops which includes Cabbage, Cauliflower and Broccoli.
Despite the challenge taken up by the farmers in enhancing production and opting to vegetable commercialization, they are always confronted with problems like the menace inflicted by pests and diseases. One rampant pest curtailing cole crop production is the infestation of Cabbage White Butterfly(Pieris brassicae).
This has however led to the use of hazardous pesticides. Though the use is on a limited scale at the moment, it might lead to its indiscriminate use over the years. Then the danger of the pests developing resistance to the pesticides and the problem of pest resurgence coupled with the residual effect that it would leave on soil, and the corresponding environmental damage might ensue if we resort to its indiscriminate use.
Therefore, a need to explore means of organic pest control is strongly felt. In line with this, an effort in studying the efficacy and the economics of using such locally prepared bio-repellents as well as the ease with which the materials can be obtained in the locality is a prerequisite step before recommending and or taking the technology to the farmers' field.
2. Objectives:
Despite the challenge taken up by the farmers in enhancing production and opting to vegetable commercialization, they are always confronted with problems like the menace inflicted by pests and diseases. One rampant pest curtailing cole crop production is the infestation of Cabbage White Butterfly(Pieris brassicae).
This has however led to the use of hazardous pesticides. Though the use is on a limited scale at the moment, it might lead to its indiscriminate use over the years. Then the danger of the pests developing resistance to the pesticides and the problem of pest resurgence coupled with the residual effect that it would leave on soil, and the corresponding environmental damage might ensue if we resort to its indiscriminate use.
Therefore, a need to explore means of organic pest control is strongly felt. In line with this, an effort in studying the efficacy and the economics of using such locally prepared bio-repellents as well as the ease with which the materials can be obtained in the locality is a prerequisite step before recommending and or taking the technology to the farmers' field.
2. Objectives:
v
To identify the most suitable organic pest control
measures keeping in view its efficacy, availability, economics and
applicability in our local conditions against common and destructive pests.
v To
explore eco-friendly measures of pest control that would contribute to
sustainable agriculture.
3. Materials & Methodology
The trial was carried out in RCBD (Randomized Complete Blovk Design) experimental design with 5
treatments including control and 3 replications. In total, there were 15 plots
of 6 sq. m. dimension each. The plants were indented at a spacing of 30*45 cm.
The trial area of 90 sq. m. encompassed a total plant population of 585.
 |
| Nursery Raising, dated 24/02/15 |
 |
| Seedlings ready to be transplanted, dated 8/04/15 |
A total of 5 treatments viz.; Garlic brew, stinging nettle
& cow urine extract, wood vinegar and Artemisia leaf extract including
control were used. The treatment application started a week after
transplanting and continued on weekly basis. The method of application resorted to was
foliar application with knapsack sprayer. A total of 9 applications were
sprayed until it was stopped a week before harvesting.
The plants were visually inspected for the
incidence of pests as well as the insect feeding damage on weekly basis
simultaneously with the treatment application. The total number of
plants with insect feeding damage and total yield per plot were also recorded
ultimately.
 |
| Pests observed: Diamond Back moth (left); Cabbage white butterfly larvae (right) |
 |
| Visual inspection of plants for insect feeding damage |
3. Result & Discussion:
The crop
reached its harvestable maturity in a span of 114 days after sowing. The
details of the recording are as illustrated in the table 1.
Table 1: Observation on plants infested by insects
and Yield
Treatments
|
No. of plants with insect feeding
damage
|
Yield(Kg)
|
R1T1
|
4
|
20.8
|
R1T2
|
2
|
28.66
|
R1T3
|
5
|
27.8
|
R1T4
|
2
|
21
|
R1T5
|
6
|
18.14
|
R2T1
|
2
|
18.96
|
R2T2
|
0
|
17.52
|
R2T3
|
5
|
15.84
|
R2T4
|
3
|
18.06
|
R2T5
|
10
|
16.52
|
R3T1
|
2
|
19.36
|
R3T2
|
0
|
20.98
|
R3T3
|
8
|
16.96
|
R3T4
|
1
|
15.52
|
R3T5
|
5
|
17.5
|
Table 2: Yield/plots and yield/acre
Treatments
|
Avg. number of
plants infested/plot
|
Avg.Yield(Kg)/
plot
|
Yield/acre(MT)cre(MT)
|
T1(Garlic brew)
|
2.67
|
19.71
|
13.14
|
T2( Stinging nettle & cow urine extract)
|
0.67
|
22.39
|
14.92
|
T3( Wood vinegar)
|
6
|
20.3
|
13.47
|
T4( Artemisia leaf extract)
|
2
|
18.19
|
12.13
|
T5(Control)
|
7
|
18.05
|
12
|
The total number of plants infested was found to have inverse relation with
the total yield. The number of plants infested was found to be lowest in
T2 (stinging nettle and cow urine extract ) treated plots and accordingly the
yield was recorded to be the highest in the said treated plots.
On the
contrary, the control plots recorded the highest rate of infestation by pests
which yielded the lowest productivity per unit area.
 |
| The harvested cabbage heads; without any major/severe pest attack. |
Table 3: Pearson's Correlation
Yield
|
|
Yield
|
|
No. of
infested plants
|
-.205
|
Pearson’s
correlation indicated that the number of plants infested and yield are
negatively correlated at Pearson’s correlation coefficient(r) of 20%.
Table 4: One-way ANOVA for the number of
plants infested
Sum of squares
|
df
|
Mean square
|
F
|
Sig.
|
|
Between Groups
Within Groups
Total
|
88.000
27.333
115.333
|
4
10
14
|
22.000
2.733
|
8.049
|
.004
|
Total
number of plants infested were highly significantly at 0.01 significance level
between the treatments. However, the
treatments had minimal influence over the yield per unit area among the
treatments.
4. Conclusion.
It can be
deduced from the trial that a combination of stinging nettle and cow urine
extract proved to be the best treatment in warding off the commonly prevalent
pests with only 2 plants with feeding
damage in one of the replications while 2 plots in the other 2 replications
recorded zero infestation.
The treatment
also did well in producing heads of better quality and in nourishing the plants
for comparatively higher yields though there weren’t much significant variation
in the yields among the treatments.
In contrast,
the control plots recorded the highest rate of insect feeding damage of 21 and
the corresponding decrease in the yield.
Therefore, it
can be suggested that the use of stinging nettle and cow urine extract be
encouraged in our farming system.
However, this
conclusion is reached solely based on the trial data of only a single season
and the reliability of the research findings is questionable until the results
be reaffirmed by similar trials in the coming seasons.
One major
drawback of such bio-formulations/repellents is its limitation in their
storage life since it requires that the formulations be applied within 2 days of
its preparation. This along with the frequency of application that it requires might
hamper its adoption by the farming community where labour scarcity is an issue
which is always on the ascend.
