Lecture 10Organic pest management: Practices Organic pest management is not a new practice for Nepalese farmers because they were and are practicing many non chemical means of managing pests such as manual (sanitation and hand picking for e.g.) and cultural methods (use of crop rotation, resistant varieties, appropriate planting time, water management, use of well decomposed compost, mix cropping, etc), with the help of various locally available plants and their derivatives. However, the use of many of the sophisticated inputs such as microbial preparations and fabricated botanical pesticides are not common among most of our farmers. They have vast knowledge on manual and cultural methods but most of them do not have knowledge on biological method, as it is perceived now. Neither they have sufficient know how about the predators community. Organic and IPM farmers are now becoming familiar with many of the techniques and do use all the safe means, from hand picking to the use of fungal preparations to minimize the damage. Some of the marketed products, like various pheromone traps (Spodolure, Helilure, DBMlure, etc) are being common in farms especially in cucurbits. Various preparations based on such fungi like Trichoderma, Beuveria, Metarhizium anisopliae, are also available in the market and few farmers are trying them. Nuclear Polyhedrosis Virus (NPV) is becoming popular among the framers in controlling pod borer as it is to prepare in farmers fields. Similarly, Zibatu, a special preparation consisting of a group of microbial population (developed by Nepalese scientists) and EM (effective microorganism, Japanese formula and prepared in Nepal) for both pest and nutrient management are also available in the market and are common in some localities. The following table enlists the various techniques that farmers are commonly using for pest management.

Table 1. Common practices adopted by the farmers to manage the pests without chemicalSN Insect Pests Control measures

1Leaf folderLeaf folder removed with the help of thorns of bayer (Ziziphus)

2Borer, grasshopper, rice/mealy bug, blastNeem, urine and cow dung, degraded material, irrigation

3Gundhi bugClothes soaked with urine & containing dung placed in field

4Borer, rice earhead bug, sheath blightCultural operation, water management

5Mealy bug, rice earhead bugand termitesDestroying infected plants, irrigation, insect trap

6Gundhi bugGandhe paso

7Mealy bug, rice earhead bug and termitesDestroying infected plants, irrigation, insect trap

8Leaf folderBy breaking rolls or folds by thorns

9Leaf folder, borer and rice earhead bug Thorn treatment, drying the water in field

10Borer Beauvaria bassiana @ 5gm/lt

11Ghokre and fadke Field drainage

12Various lepiPestsLight trap

13Bodopteriansr and leaf folderVarious plant extracts

14Borer and leaf folderMustard cake

15Root rotSpraying cows' urine mixed with water; mix with neem water

16Mealy bugIrrigation

17Rice earhead bug and borerLight trap

Although many farmers are not familiar with biological pest control, the notion has entered into research through the collection, multiplication and redistribution of gall making fruit fly Cecidochares utilis for the suppression of banmara (Eupatorium adenophorum) weed as the first biological control program implemented in Nepal in early 1990s. Subsequently, Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) was introduced from France for the control of apple woolly aphid Eriosoma lanigerum (Hussman) (Homoptera: Aphididae). Curinus coruleus was introduced from Thailand for the control of Leucaena leucocephala psyllid (Heteropsylla cubana), Cotesia plutellae and Diadegma semiclaussaum were introduced from AVRDC, Taiwan for the suppression of diamond back moth Plutella xylostella. Some biological control agents have also been exported from Nepal. Systematic surveys of indigenous biological control agents of two important pests, Helicoverpa armigera and Rhynchocorris humeralis began in 1992 at Lumle Agricultural Centre. Trichogramma chilonis was reared at Lumle Agricultural Research Centre as well as Entomology Division, Khumaltar. Unidentified species of egg parasitoids were observed from Chitwan attacking Litchi bug, Tessaratoma papillosa. Fungal pathogen Metarhizium anisopliae attacking white grub have been isolated and manufactured for field experimentation purposes. Indigenous strains of Fungi Trichoderma spp. has been isolated and some of the species have shown promises as a potential biological control agent of several soil borne diseases Works on the isolation of indigenous strain of Bacillus thuringiensis has been initiated. Fungal pathogen Paecilomyces funosoroceus were isolated from aphids and red ants at Lumle. Many species of spiders have been identified in rice fields and are claimed to be a insect controller. However, there is hardly any evidence of application of these bio-control agents in the farmers fields. Most farmers are unable to distinguish pest insects from their natural enemies. Many farmers are unable to distinguish between the hover flies (important aphid predator) and fruit fly (serious cucurbit pest). There may be difficulty in identifying ladybird beetles and Epilachna beetles. Identification of the diversity of potential biological control agents in each crop environment through exploratory studies is the first step towards understanding and promoting biological control agents. Once identified, natural enemies can be conserved, their roles defined and their efficiency enhanced by adopting one or more of the practices such as pesticide avoidance, use of selective botanicals, provision of food, shelter or alternative hosts, etc..Experienced Farmers are having quite fair knowledge on the locally available plants with pesticidal values in their different modes of use and the targeted pests. It is estimated that there are about 2400 plants with pesticidal value and among 425 plants are found in Nepal and farmers are widely using most of them for managing various pests. The common plants being used for the purpose are neem (Azedirachta indica ), garlic (Allium sativum), pudina (Mentha arvensis), ginger (Zingiber officinalis), turmeric (Curcuma domestica), tite pati (Artemesia alatum), marygold(Tagetes patula),timur (Xanthoxylum alatum), asuro (Adhatoda visica), tulasi (Ocimum sactum), bakaino (Melia aderachata), papaya (Carica papaya), sisnu (Urtica dioica), Tobacco (Nicotianum tobacum), pire ghas (Polygonum hydropeper), sarifa (Annonaa squamosa), sital chini (Moringha oleifera), onion (Allium cepa), siundi (Euphorbia royaleana), sajiwan ( Jatropha curcus), simali (Vitex nigundo). Among these plants about 80 % work as repellant, 11.5 % antifeedant, 6% sterilant, 2 % biocidal and 0.5 % poisonus. Unfortunately, the knowledge about these plants are dissipating as the old generation passes away and new generation seems not interesting in such skills. Pervasive import of chemical pesticides, detraction of young generation to agriculture, loss of plant diversity, and lack of written document about these plants are the major reasons for this misfortune. However, due to growing knowledge about the serious negative impacts of synthetic pesticides on human and environment health, the interest on these plants are increasing both globally and locally. In recent years some commercial products mainly based on neem such as nimaban, nimarin, multineem, biomultineem are also available in the market but are imported ones. Although they me be good, however, they are not at the easy reach of common farmers neither they use these marketed pesticides frequently. Quality of the products and time of application are of crucial consideration in using such imported products. Fresh home made preparations are said to be more effective according to the farmers. Many research works have also been done verify the farmers practice using various plant materials against different insect pests and nematodes. Among the tested plants, sweet flag (Acorus calamus), Neem (Azadirachta indica), Boke timur (Xanthoxylum armatum) and rape seed (Brassica compestris var. toria) have provided good control of grain weevils (Sitophilus spp, Bruchus spp and Callosobruchus chinensis). The following table gives a picture of farmers experience in the use of locally available plant materials for managing the common insect pests. Many research works still have to be done to generate authentic data base pertaining to the efficacy of the plants, mode of action, chemistry involved, appropriate preparation concentration and, so on, to come with concrete recommendation to make the use of these locally available, cheap and safe materials wider and practical. The following table gives the glimpse of farmers experience on the use of these plants.

Table 2.Some examples of the farmers experience on managing the pests with botanicals SNPestPlants usedRemarks

1.Grain Weevils Sitophilus spp. , Bruchus sps. and Callosobruchus chinensis Sweet flag (Acorus calamus), Neem, ( Azediracha indica), Boketimur ( Xanthoxylum armatum), rape seed (Brassica compresris var toria) Good Control

2.Vegetable crops (Cole crops (cauli,cabbage,Rao) urnip, onion, beans, brinjal, Asuro (Justicia adhtoda), Simali (Vitex negundo), Neem, bakaino, (Melia azederach), pyrethrum sps, Siltimur (Lindera neesiana), Pyrethrum (Chrisanthemus cinerariafolium), tobacco (Nicotiana tabacm)elderberry (Sabacus sp), Boke timur (Xanthoxylum armatum), Mmentha (Mentha arvensis), Gandhe (Ageratum conyzoides), Hemp (Canabis sativa), Lemon (Citrus lemon), Custard apple (Annona reticulata), and Sopa berry Rittha (sapindus marginatus) Mixed results

3.Root knot (Meloidogyne javanica) of Okra Green leaves of Neem, bakaina, Sunhemp, (chlorolaria juncia) Dhaincha (Sesbania acculiata) Good result

4.Red Ant, Potato Mulching with Dhurse ( Buddleia asiatica),Asuro Titepti ( Artemisia vulgaris) , Khirro Good Result

5.Coffee (Stem borer) Marigold, Bakaina/Neem leaves, garlic and linseed oil Good prevention

6.Black rot of coffee and citrus (Fungus) Siundi (Euphorbia royaleana) Sajiwan ( Jatropha curcus) Besar ( Curcuma domestica) and water Good prevention

7.For sucking insectsGiti malGod result

8Aphids (Brevicoryne brassicae) of crucifers and legumesdry wood ash in the early morning, Wood ash soaked in water (1:4) for 12 hours filtered and mixed with soap water and sprayed. Good result

9Most of the insectsCow urineGood result

10Root knot ( Meloidogyne javanica) of Okra

Green leaves of Neem, bakaina,Sunhemp,( chrotolaria juncia) Dhaincha ( Sesbania acculiata)

Good result