FARMER'S NOTEBOOK
Managing pollu beetle in black pepper
M.J. PRABU
|
Pest infestation is seen more in the plains than at high altitudes
|
Photo: IISR
EARLY SYMPTOM: Infested leaves show numerous small holes on their surface .
BLACK PEPPER, a major spice crop in India, is vulnerable to several infestations of which the pollu beetle (Longitarsus nigripennis) is the most serious.
The pest infestation is more in the plains than at high altitudes.
However, infestation by the pest at higher altitudes in Idukki district of Kerala and Kodagu district of Karnataka is reported to be increasing during recent years.
Main reason
Changing environmental factors at higher altitudes are probably the main reasons for the increasing occurrence of pollu beetle in these regions in recent years, according to Dr. S. Devasahayam, Principal Scientist, Indian Institute of Spices Research (IISR), Kozhikode, Kerala.
Adult Pollu beetles measure about 2.5 mm x 1.5 mm in size, and scrape and feed on tender leaves, spikes and shoots which grow during the onset of monsoon in May-June.
The feeding activity of beetles results in the formation of black sunken patches on the tender shoots and spikes and small irregular circular holes on the surface of the tender leaves.
Early symptoms
"Presence of numerous small holes on the surface of the tender leaves is a characteristic early symptom of the occurrence of the pest population in the plantation," said Devasahayam.
Female beetles lay eggs on tender berries. The eggs hatch in 3-8 days into minute creamy-white grubs.
The grubs bore into the berries and feed on the internal contents and make them hollow.
Infested berries turn pale yellow initially and later, black, and crumble when pressed by hand. The grub period lasts for 20-40 days. A single grub destroys 2-3 berries during this period.
Fully-grown grubs drop down on the soil and pupate in earthen cocoons and emerge as adults after 6-8 days.
The adults stop laying eggs when the berries mature during November-December. With the onset of monsoon showers, they resume their normal feeding and breeding activities.
The pest infestation is higher in the plantation during September-October and is very severe in shaded areas of the plantation, according to Devasahayam. Vines that are trailed on trees such as those of jack and mango trees, that produce heavy shade in homestead gardens are severely prone to this infestation.
Integrated management
Attempts to develop an integrated management practice against this pest are being made at the Institute, according to him.
No major natural enemy of the pest has been identified so far.
A few wild pepper species have been identified to be field resistant to the pest and these are being utilised to develop resistant varieties, he explained.
Cultural practices
Cultural operations such as pruning the branches of the trees on which the vines are trailed are important to reduce the pest population.
Spraying 0.5 per cent quinalphos twice a year, during July (or one month after berry set and in October was found to be effective.
Similarly neem-based insecticide such as Neemgold 0.6 per cent was also found effective.
Other options
Alternate sprays of quinalphos during July followed by 3-4 sprays of neemgold during August-October at 21-day intervals may also be done.
"Since the spraying operations coincide with the monsoon season, the insecticides are to be sprayed when there is sufficient gap in the rains," Devasahayam explained.
The underside of leaves are also to be sprayed thoroughly since the adults are generally found feeding and resting in this region.
For more information readers can contact Dr. S. Devasahayam, Principal Scientist, Indian Institute of Spices Research (IISR), P.O. Marikunnu, Kozhikode 673012, phone: 0495 - 2731410
Printer friendly
page
Send this article to Friends by
E-Mail
Sci Tech
