Being a farmer one’s knowledge of insects goes much beyond the cockroach, the mosquito and the ant et al. One is suddenly thrown into the vast world of insects, beneficial or otherwise. With each day, the change of seasons and years one earns the reputation of being an amateur entomologist of sorts among ordinary mortals. Recognising whether the insect is friendly or inimical makes you an aware-farmer and prepares you to battle them or use them as an ally.
This March I had the opportunity to visit the Dapoli-based Konkan Krishi Vidyapeeth while attending an international conference and happened to befriend a genial entomologist, Dr Shekhar Mehendale who not only took me around the city’s neighbourhood showing me what it offers a tourist, like the century-old temple with its huge copper bell and the inviting, languid beach. But it was the few hours spent in the Entomology Department’s Insect Museum which made the trip memorable. It was my first visit to an insect museum and thousands of insects displayed according to their family made me realise the importance of the critters.
A mentor and guide to a dozen or so doctorates, Dr Mehendale is a storehouse of information when it comes to the world of insects. Here in a chat with Hiraman he dwells on the importance of insects, the farmer-friendly insects,biological control, pest management etc.
On the insect museum
We have the best collection of insects among the four agri universities in Maharashtra. Most of our specimens have been collected by students as part of their study. The Konkan region is rich in biodiversity, thanks to its insects, the vegetation and the tropical climate. In short, it’s a haven for various types of insects. Insects here are distributed in line with the crops of this region e.g. Mango Hoppers, Rhino Beetle, Red Palm Weevil, Tea Mosquito which affects the cashew crop and some pests of rice, a commonly grown food crop. Here we have about 25-26, out of 29 orders given in Imms’ General Text Book of Entomology. The major orders in the collection are Coleoptera, Lepidoptera, Diptera, Hemiptera, Hymenoptera, Odonata and Orthoptra. Apart from them some others like Neuroptera, Isoptera, Embioptera, Phasmida, Ehemeroptera, Trichoptera, Mecoptera, Dermaptera etc are also in the collection. Specimen brought to the Department usually comes to me first. My interest in entomology is due to my guru, Dr. Anil Powar, presently vice president of Indofil Chemicals, Mumbai. It was he who aroused my interest in the subject. During my college days I had the opportunity to work under him. Whatever I have achieved in my life I credit it to him.
On the study of insects
Just two lines will explain everything: ‘Battle between man and insects is as old as civilization which was there in the past, is still continuing and will be there in future too’. It’s also said that insects accompanies man from his cradle to grave. Hence to understand them we need to study them. Their numbers are huge compared to the animals and we continue to come across new varieties very other day. The history of insect identification is quite old and dates back to the Vedic period where Prasastapada classified the whole animal kingdom in to two–Ayonija and Yonija. The former was again grouped as Swedaja, Usmaja, Udwija and Andaja (included insects). Aristotle classified insects initially into two groups Haustallets and Mandibulates. He formulated four insect orders as Coleoptera, Dipeta, Hymenoptera and Lepidoptera, even earlier than the Swedish botanist and zoologist Carl Linnaeus. Linnaeus in his 10th edition of Systema Nature formulated rules of classification and thereafter the binomial names came in to existence. During the British rule in India lot of good work on insects happened. Sir Maxwell Lefroy was appointed as the first government entomologist. He was followed by J.C Fabricius, Koening , Sir Ronald Ross (the man who studied mosquito for malaria parasite) etc. The museum concept was created and enriched by the Britishers and the title curator of museum came in to existence. Dr. Horsefield was the first curator of British Museum at Kolkatta. The Bombay Natural History Society was founded in 1883. The Zoological Survey of India (ZSI), was also founded by the Britishers. They published special monographs on Butterflies and Moths of India, Ants of India, Termites of Thanjawar district etc.
On insects waiting to be identified
There are still insects waiting to be found, identified and given a name. Identification becomes tricky and difficult as the organism becomes smaller and smaller. Insects abound in huge numbers and in varying number of species, subspecies etc. We have very few organisms are like them. Take elephants, which is limited to just two species. If you take the example of cockroaches, bees or dragonflies they are at least dozens of them. Hence insect identification is not as easy as compared to the higher animals. It’s an ongoing and continuous process. Take the case of Mantophasmatidae which is a family of carnivorous insects within the order Notoptera, which was discovered in Africa in 2001.
On making insects as allies
Some are pests while some predators. All insects are not harmful. There are many which are useful and beneficial to us. Most of the adult insects need a good source of carbohydrates, amino acids, sterols, fat etc for which they visit the flowers for its nectar resulting in pollination, a win-win situation for both. The list of the flowering plants a farmer should have is vast. I can think of maize, cowpea, surangi, mustard, coriander, fennel, carrot, raddish, castor, sesame etc. Ornamental plants like Kuphia, Gilardia, Cockscomb, Dahlia, Aster, Marigold, etc can be planted in one’s garden or farm plot to derive benefit of pollinators and predators and parasitoids. This concept is called Ecological Engineering or Habitat Manipulation and also forms a part of the ‘push and pull technique’ of pest management.
On biological control of insects
All insects in the distant past lived in a state of harmony, what we call as General Equilibrium Position (GEP), maintained by action of abiotic and biotic factors over a period of time. All insects which do not damage our crops are beneficial to a farmer, namely the scavengers, pollinators and natural enemies of pests. A good example of this is a forest ecosystem undisturbed by human interventions. So long as man was lead a nomadic existence everything was fine. But when he learned to cultivate the land the problem began. The ushering of the Green Revolution changed the concept of agriculture due to crop improvement, fertigation, pesticides, biotechnology etc. which disturbed the balanced ecosystem, thanks to our hunger for more. And that’s when the insects became pests. Bringing back a balance is difficult but not impossible. The answer lies in adoption of IPM (Integrated Pest Management) or INM (Integrated Nutrient Management) etc with judicious use of resources like water, fertlilizers and pesticides. Besides promoting biological control wherever possible. Using some simple tillage operations, use of trap crops, crop rotation, use of crop refuge, maintaining unutilized area, use of plant origin insecticides, light traps, sticky traps, pheromone traps etc can be of immense help. Decreasing our dependence on chemical fertilisers and pesticides, using selective insecticides with proper dose that too only when required, keeping pest residue as food for natural enemies, not mixing two/ three insecticides unless advised–can considerably bring down the damages incurred by the pests. We need to remember: Nobody can completely control the insects and it is not required too. We need to follow the concept called, ETL or Economic Threshold Level. As a Sanskrit saying goes: ‘Jivo Jivaschya Jivanam.’
On reaching out to farmers
Whatever I’ve gained I’m eager to share. I do contribute articles in newspapers, give talks on radio, pay regular visits to farms and is active on What’s Up. Beside the queries from farmers in the region I have been receiving queries from farmers in Karad district on certain pest problem. Recently, a farmer sent me images of leaf miner problem on Red Pumpkin in which 50 per cent of the leaves were infested. It was a serious infestation and I advised him to spray Cartap Hydrochloride @ 15 g per 10 lit. He followed the advice, sprayed it and a week later called up to say that about 90 %) larvae were dead. This insecticide is of biological origin synthesized from Marin Annalid- Lumbrinaris heteropoda.