In the previous season of apple cultivation in Kashmir, farmers were encountered by unusual black stains (”haii” in Kashmiri language) on leaves, stems, twigs and also on fruits. Though most of the framers sprayed different kinds of insecticides while noticing the symptoms of this insect present on ariel parts of Apple tree. Fortunately, apple fruit was not affected to a large extent, what ever unusual was present on the fruit was washed away by mechanical cleaning of grading and packaging. But this aggravates the problems to farmers, who are small and marginal ones because of their lower capacity to transport their produce for scientific grading and packaging.These symptoms were caused by an insect called as Green Apple Aphid. Both nymphs and adults suck phloem from their hosts and prefer to feed on succulent, young tissue. Aphids may be found feeding on the underside of leaves, on growing shoot tips or the shoot stem. When populations are high, the upper leaf surface will also be colonized. High populations early in the year may also feed directly on developing fruits, causing small bumps and red spots to appear at the feeding sites. The most important damage from these aphids is generally caused by the presence of sparse amounts of honeydew excreted by the aphids. When this honeydew drips onto the fruit, it is often colonized by a black, sooty fungus, which causes russeted areas on the fruit, especially around the stem.This honeydew is extremely annoying to harvesting & pruning crews.
Reason for outbreak of Green Apple Aphid in Kashmir:
There are various causes responsible for outbreak of insect pest, like temperature, monoculture, introduction of new varieties, resistance of pests & indiscriminate use of chemicals, killing of natural enemies and the rest.
When pesticide is used indiscriminately against a target pest over a period, there is always a chance of resurgence of non-target pests or outbreak of secondary pests, which ultimately outnumbers the target pest and insignificant pest attains the status of economic problem. This problem is compounded by usually relaying only on chemical pesticides. In brief, it can be said that whenever a chemical control is focused on controlling the pest of economic problem, there will be always a danger of resurgence of minor pests and with time they attain the status of target pest.
The main reason is killing/weakning of natural enemies population density present in the environment by indiscriminate use of pesticides, which otherwise keeps a check on minor pests population density. Insect resurgence occurs when an insecticide treatment destroys the pest population and kills, repels, irritates or otherwise deters the natural enemies of the pest. The residual activity of the insecticide then expires and the pest population is able to increase more rapidly and to a higher abundance when natural enemies are absent or in low abundance. Another reason is developing resistance over a period of time by reapedtly using the same pesticide season after season.
What can be done:
The farmer should always focus on IPM. Integrated pest management (IPM) combines the use of biological, cultural and chemical practices to control insect pests in agriculture production. It seeks to use natural predators or parasites to control pests, using of selective pesticides for backup only when pests are unable to be controlled by natural means.It does not discourage spraying chemicals; it promotes spraying with selective pesticides only when the crop needs it, which generally means that less pesticide is used.
Conclusion:
Evolution of modified versions of insect pests and resurgence of minor insects is a continuous process & will remain always in the nature as long as hosts (Apple trees) are there. This clearly demands the adoption of practices that keeps the population of insect pests below economic injury level, as complete elimination has never been objective of any control method neither it is possible through any control method. This further necessities the adoption of Integrated pest management. The use of same insecticide/ fungicide season after season must be avoided for long term control benefits, otherwise there are high chances of farmer complaint about effectiveness of pesticide after 3-4 years.
The farming community must follow recommended spray schedule of SKUAST-K in letter and spirit. The farmer should always consult a relevant technical expert for advice and at the same should also apprise the expert about the previous seasons spray. The recent example of avoiding the instructions of recommended spray schedule can be gauged from the fact that various orchardists skipped Horticulture Mineral Oil (HMO) spray and replaced it with copper based fungicides on just a mere imagination rather on any knowledge that copper based fungicides will eradicate the previous year Green Apple Aphid and wash away the black stains (honeydew excreted by the aphids) on stems and trunk of apple trees. This Green Apple Aphid must be given due importance during this season as there are high chances of its outbreak during this season.
The writer is working in APD&FW as Junior Agriculture Extension Officer. Mail: [email protected]. Views expressed are his own.
