Abstract: The present study was undertaken with aim to provide sustainable management of Scutellerid bugs by some IPM components due to major pest of Jatropha through out the world. The field experiments were carried out on Jatropha curcas L. plantation already made at Rajiv Gandhi South Campus, Barkachha, Mirzapur to evaluate damage potential and efficacy of some IPM components against scutellerid bug infesting Jatropha during 2009 and 2010. The experiment on the damage potential of Scutellera nobilis showed an increase in damage with increasing population. Two bugs/plants did not cause significant damage, while 20 bugs per pants resulted in more significant damage than previous one. Two foliar sprays given at monthly interval revealed that lambda-cyhalothrin 5 EC at 25 g a.i. ha-1 and imidacloprid 17.8 SL 100 mL ha-1 were most effective treatments followed by carbosulfan 25 EC at 250 g a.i. ha-1 and monocrotophos 36 SL at 500 g a.i. ha-1. Next effective treatments were spinosad, endosulfan, Beauveria bassiana, Metarhizium anisopliae resulted in moderately reduction in pest population. All Insecticides showed maximum reduction of bug population during 3rd days after treatments in both sprays, whereas in case of botanical and bioagents maximum reduction was noticed during 7th days after treatments in both sprays. Chlorpyriphos 50 EC at 250 g a.i. ha-1 and neem oil (2%) were found least effective and exhibited minimum reduction in bug population as compared to other IPM components.
INTRODUCTION
Jatropha curcas L. a genus of Euphorbiaceae is a native of Mexico and tropical America but Naturalized now throughout the world. Jatropha, fuel of the future is reported to be cultivated in Central and Western parts of India and also Southern states. By blending Jatropha oil based biofuel as an extender with diesel at a ratio of 1:5, the country can save annually Rs. 17,000 crores in foreign exchange. Globally more than 40 species of insects affecting Jatropha have been reported. A global list of phytophagous insects consisting of 60 species in 21 families and four orders has been compiled in Australia, where it is considered as a weed. Particularly noteworthy is the insect order Heteroptera that has at least 15 species in Nicaragua, which can extract nutrients from physic nut (Manoharan et al., 2006). A global list of phytophagous insects consisting of 60 species in 21 families and four orders has been compiled in Australia, where it is considered as a weed (Manoharan et al., 2006). Serious damage by Nephopteryx larvae was observed at Pusa and Mandalay (Hampson, 1912). Manoharan et al. (2006) recorded more than dozen pests occurring in Jatropha (Devi et al., 2008) reported that the two insect pests that are emerging as a major problem in Jatropha cultivation are the scutellarid bug Scutellera nobilis Fabr. that causes flower fall, fruit abortion and malformation of seeds and Pempelia morosalis that causes webbing of inflorescence and capsule damage.
Scutellarid bug, Chrysocoris purpureus was recorded in North Western provinces, Sikkim, Calcutta, Assam and several parts of South India including Pondicherry (Kershaw and Kirkaldy, 1908). Several different species of true bugs have been found to feed on Jatropha curcas (Grimm and Maes, 1997). In India, the production is also hampered by a few hemipteran insect pests, of which scutellerid bugs, Scutellera nobilis (Fabricius) and Chrysocoris purpureus (Westw.) (Shanker and Dhyani, 2006) are found to be very serious. Hence, present investigation was undertaken to find out damage potential of Scutellerid bugs and their management by some IPM components.
MATERIALS AND METHODS
The present investigation was carried out on about 300 ha Jatropha plantation already made at Rajiv Gandhi South Campus, Barkachha, Mirzapur, Uttar Pradesh, India during April 2009 to May 2010.
Determination of Damage Potential
The damage potential of bug S. nobilis was assessed by confining
a known number of nymphs on the green pods in the potted plants. Scutellerid
nymphs prestarved for 4 h were released at the rate of 2, 3, 5, 9, 12, 15 and
20 per bunch in plant itself and covered with perforated polythene bags to confine
the insects. Green pods of similar size were selected in the same plant and
covered with perforated polythene bags, which served as control. The treatments
were replicated five times. The damage was assessed on seventh and fourteenth
day after the release of the bugs and the loss over control was computed by
taking final weight of damaged pods.
Evaluation of IPM Components Against Scutellerid Bug
The insecticidal trials were laid out in randomized block design with three
replications, each in 12 x6.5 m plots keeping 2 m row to row and 1.5 m plant
to plant distance. Five plants were selected at random and tagged in each plot
for determination of bio-efficacy of some IPM components against scutellerid
bugs. All the agronomical practices were followed to raise the crop. There were
thirteen treatments and the treatments consist of endosulfan 35 EC, cholpyriphos
50 EC, Monocrotophos 36 SL, profenophos 50 EC, spinosad 45% SC, Lambda-cyhalothrin
5 EC, indoxycarb 14.5% SC, carbosulfan 25 EC, imidacloprid 17.8 SL, neem oil,
Beauveria bassiana, Metarhizium anisopliae and untreated control
(water spray). The first insecticidal application was initiated when the population
of S. nobilis reached at below Economic Injury Level (EIL) and repeated
the second insecticidal spray at 30 days after first spray. In both the insecticidal
sprays pre-spray count of scutellerid/plant was also taken. The percent reduction
over control was recorded for each treatment. Five plants were selected at random
and tagged in each plot for counting the bug population and weekly observations
were recorded on the entire tagged plant throughout the crop season. Pre-treatment
population of S. nobilis was recorded 24 h before the spray. Post treatment
population was recorded at 3 and 7 days after spraying. Efficacy of different
treatments in controlling the scutellerid bug was determined by calculating
percent reduction with the formula given by Henderson and
Tilton (1955) as under.
Where:
| Ta | = | No. of insects after treatment |
| Tb | = | No. of insects before treatment |
| Ca | = | No. of insects in untreated check after treatment |
| Cb | = | No. of insects in untreated check before treatment |
RESULTS AND DISCUSSION
Determination of Damage Potential
Considering the extent of damage of scutellerid bug on pods, two bugs/plant
did not bring out in measurable weight loss of pods during both the years, while
nine bugs per plant resulted in a mean weight reduction of 0.24 and 0.29 g pods
within seven days during 2009 and 2010, respectively. This was progressively
increased to 0.43 and 0.48 g in both the years, respectively when the bug population
was 20 per plant. Results are shown in Table 1 for 2009 and
2 for 2010. However, the losses were assessed at 14 DAR, even two bugs perplant
could reduce the pod weight to tune of 0.09 and 0.20 g in 2009 and 2010, respectively,
while at 20 bugs per plant resulted in 0.56 and 0.60 g weight loss in both the
years, respectively. The reduction in weight due to feeding was more during
first 7 days period of feeding than the subsequent 7 days. The weight loss due
to bug feeding was very less even if they were allowed for 14 days. The reason
might be due to the longer period for causing the damage and ability of the
plant to recoup the damage caused. Similar method for assessing the damage potential
of pod bug and pod fly was reported by Kumar and Nath (2003).
These results are in concurrence with the findings of Ambika
et al. (2007), who computed damage potential of scutellerid bugs
on Jatropha (Table 2).
| Table 1: | Damage potential of Scutellerid bug on Jatropha during 2009 |
| Values in parenthesis are |
|
| Table 2: | Damage potential of Scutellerid bug on Jatropha during 2010 |
| Values in parenthesis are |
|
| Table 3: | Integration of some IPM components against Scutellerid bug infesting Jatropha during 2009 |
| *Arcsine-transformed values and in parenthesis are retransformed percent values, DAT: Days after treatment | |
First Spray 2009
Data presented in Table 3 showed that all the treatments
were significantly superior over control at three and seven days after first
spray during 2009. Third day after spraying, amongst the different IPM components
investigated against scutellerid bug, lambda-cyhalothrin causing maximum percent
reduction (77.37) in bug population which was statistically at par with the
imidacloprid (77.19%). Carbosulfan (70.70%) was found statistically at par with
the monocrotophos (70.35%) and spinosad (69.78%). Endosulfan (56.86%) and indoxycarb
(55.56%) were found moderately effective against scutellerid bugs which showed
non-significant reduction in bug population with the results obtained by Beauveria
bassiana (56.54%) and Metarhizium anisopliae (55.78%). Next treatment
was profenophos causing 50.40% reduction in scutellerid population. Chlorpyriphos
(45.67) and neem oil (44.12) gave least percent reduction in bug population.
It is evident from Table 3 that 7th day after spraying, imidacloprid performed the best and the percent reduction was 71.72 and it was significantly superior to all other treatments. Lambda-cyhalothrin gave 69.44% reduction in population which was significantly superior to other IPM components except imidacloprid. Application of carbosulfan and monocrotophos brought about population reduction from 68.10 to 67.83%, respectively which were at par with each other and were found non-significant with spinosad (67.49%). Bioagents, i.e., Beauveria bassiana and Metarhizium anisopliae were found significant with each other resulted in percent reduction ranged from 63.33 to 61.85%, respectively. The efficacy of indoxycarb and endosulfan were 50 and 49.16%, respectively, which were statistically at par with each other. Neem oil (46.69%) and profenophos (45.34%) showed least percent reduction in bug population, which were statistically at par with each other. The lowest scutellerid bug population reduction (42.38%) was observed in chlorpyriphos.
Second Spray 2009
Data recorded in Table 3 showed that the highest percent
reduction in bug population at 3rd day after spraying was found in imidacloprid
(78.91) which was found statistically non-significant with lambda-cyhalothrin
(78.48%). The Next effective treatment was carbosulfan resulted in 75.20% reduction
in bug population. The spray of monocrotophos (73.08%) was found statistically
at par with that of spinosad (71.27%). However, application of endosulfan, M.
anisopliae and indoxycarb resulted in 60.20, 59.13 and 58.62% reduction
in bug population, respectively which were at par with each other. B. bassiana
(56.83%) was found statistically at par with that of indoxycarb. Chlorpyriphos
exhibited least efficacy (53.01%), which was at par with profenophos (52.81%).
Neem oil gave minimum 44.37% reduction.
All the treatments were found superior over control at 7th day after spraying (Table 3). Lambda-cyhalothrin, which gave 75.73% reduction followed by imidacloprid (74.52%) and they were statistically at par with each other. Spray of carbosulfan resulted in 71.10% reduction and showed non-significant results with that of monocrotophos (69.64%) and spinosad (69.30%). However, B. bassiana (67.90%) was found at par with monocrotophos and spinosad. The next effective treatment was M. anisopliae followed by endosulfan showed 63.52 and 56.67% reduction in bug population, respectively. Neem oil (54.10%) and indoxycarb (53.33%) were found statistically at par with each other. Chlorpyriphos showed minimum 45.83% reduction in scutellerid bug population.
First Spray 2010
Third day after spraying lambda-cyhalothrin was found significantly superior
than all other treatments and showed 75.43% reduction in bug population (Table
4). The next effective treatment was imidacloprid which was statistically
at par with carbosulfan resulted in reduction varied from 72.23 to 71.26%, respectively
for both the treatments. Spray of monocrotophos (68.70%) was found at par with
spinosad (67.57%). The results revealed that M. anisopliae resulted in
60.16% reduction and it was statistically at par with B. bassiana (59.88%).
However, endosulfan offered 58.33% reduction, which was at par with B. bassiana.
The efficacy of indoxycarb and profenophos were 54.55 and 53.70%, respectively,
which were at par with each other. Chlorpyriphos exhibited 44.44% reduction
in bug population. The minimum reduction (39.25%) was observed in neem oil.
Data presented in Table 4 showed that lambda-cyhalothrin recorded highest reduction (71.78%) in bug population followed by imidacloprid (70.84%) and were found statistically at par with each other during 7th day after spraying. In case of carbosulfan and M. anisopliae percent reduction ranged from 68.97 to 67.40, respectively and did not differ significantly. Monocrotophos and spinosad exhibited percent reduction from 67.14 to 66.64, respectively and were at par with each other and also with bio-agent M. anisopliae.
| Table 4: | Integration of some IPM components against Scutellerid bug infesting Jatropha during 2010 |
| *Arcsine-transformed values and in parenthesis are retransformed percent values, DAT: Days after treatment | |
The next effective treatment was spray of B. bassiana which gave 63.89% reduction followed by endosulfan recorded 54.17% reduction in scutellerid population. The efficacy of indoxycarb and profenophos ranged significantly from 52.27 to 50%, respectively. In case of neem oil only 45.33% reduction was observed, while chlorpyriphos recorded minimum reduction (37.49%) in bug population.
Second Spray 2010
The spray of Monocrotophos at 3rd day after treatment application was found
most effective against scutellerid bug resulted in 74.70% reduction followed
by carbosulfan (73.87%) and both the treatments were found statistically at
par with each other (Table 4). While, in case of imidacloprid
73.01% reduction was observed and did not differ significantly with carbosulfan.
Effectiveness of imidacloprid and spinosad were 72.94 and 72.59% and showed
non-significant results with each other and that of imidacloprid. Indoxycarb
and B. bassiana recorded similar reduction (61.43%) in bug population
and efficacy of both the treatments were at par with the results obtained by
M. anisopliae (60.88%) and endosulfan (60.63%). Profenophos (57.65%)
was found significantly superior to neem oil (48.60%) and chlorpyriphos (48.57%).
Neem oil and chlorpyriphos were at par with each other.
The data recorded on percent reduction in bug population (Table 4) indicated that management schedule consisting of spray of imidacloprid showed maximum reduction (72.62%) and was found at par with that of carbosulfan (72.23%) and monocrotophos (72.01%) at 7th day after spray. The next effective treatment was lambda-cyhalothrin resulted in 70.58 % reduction and did not differ significantly with lambda-cyhalothrin. M. anisopliae and spinosad maintained their effectiveness showing 69.39 and 69.35% reduction in scutellerid population and were at par with each other and that with lambda-cyhalothrin. The efficacy of B. bassiana was 66.46%. The mean reduction in bug population in endosulfan and indoxycarb ranged from 55.98 to 55.28%, respectively and were found statistically at par with each other and that of neem oil (55.18%). The spray of profenophos recorded 53.97% reduction and did not differ significantly with indoxycarb and neem oil. Chlorpyriphos gave minimum population reduction (44.09%) of scutellerid which was found significantly inferior to all other treatments.
Tuncer et al. (2002) have also reported that lambda-cyhalothrin was the most effective in controlling bugs (Palomena prasina and Gonocerus acuteangulatus. Singh et al. (2008a) conducted bioassay to evaluate bio-efficacy of 11 insecticides and found that Carbosulfan (0.02%) and lambda-cyhalothrin (0.007%) were the most effective, resulting in 100% mortality within 24 h under all modes of treatment. Dikshit and Lal (2002) have evaluated the bioefficacy of imidacloprid (Confidor 20 SL) against black citrus aphid (T. aurantii) at 1.25 ml L-1 and reported 53.78% aphid control after 24 h of application while after 3 days, an excellent control (99.21%) was noticed and remained effective thereafter up to 15 days. Vega Bernal (2003) was also found confidor 70 WG most effective against whitefly in tomato crop. Gupta and Shanker (2007) have also reported that imidacloprid (22.5 g a.i. ha-1) showed maximum reduction (79%) in mealy bug population in tea plantation. These observations are in consistent with Das et al. (2000) and Kumar et al. (2005), who observed monocrotophos and carbosulfan to reduce the tea mosquito bug population effectively on cashew. Ambika et al. (2007) observed that carbosulfan 0.025% was found to be effective followed by monocrotophos 0.045% for controlling the scutellerid pests (S. nobilis and C. purpureus) in Jatropha.
In present experiments bio-efficacy of insecticides was more at 3rd days after spraying as compared to neem oil and other bioagents and at 7th days after spraying it was continuously decreased resulted in less reduction in pest population. Whereas, in case of neem oil and other bioagents at 3rd days after spraying percent reduction in bug population was less and it was continuously increased and found maximum at 7th days after spraying. However, the findings of the present study were further strengthened by earlier observation of Singh et al. (2008b), who reported maximum reduction of okra jassid by insecticides at 3rd days after insecticidal spray. The present findings are in agreement with those of Mandal et al. (2007) when insect treated with B. bassiana reduced the feeding rate within 7 days after application resulted in maximum reduction in pest population at 7th day after spray. The biocontrol agents tested were slow acting on scutellerid bugs (Sridevi et al., 2004).