www.IndianJournals.com Members Copy, Not for Commercial Sale Downloaded From IP - 14.139.186.22 on dated 25-Apr-2016 Synergistic action of neem and karanj to aphids and mites Vishal Kumar, K. Chandrashekar and Om Prakash Sidhu* Biomass Biology Division, National Botanical Research Institute, Rana Pratap Marg, Lucknow - 226 001, Uttar Pradesh, India ABSTRACT Methanolic extract of neem (Azadirachta indica L.) and karanj (Pongamia pinnata Pierre) oil enriched in azadirachtin and karanjin respectively were tested alone and in combination against Tetranychus species and chrysanthemum aphid Macrosiphoniella sanborni. The combined formulation consists of methanolic extract of neem (NSOME) and karanj oil (PSOME) was very effective (LC 50 0.11%) and showed 70 and 11.36 fold increase in activity over NSOME (7.7%) and PSOME (1.25%) alone in laboratory against T. species. Field studies were conducted on Tetranychus species infecting Withania somenifera. The combined formulation provided more than 90% protection at the lowest concentration (0.25%), whereas PSOME and NSOME provided only 78.6 and 71.9% protection even at the highest concentration (1%) tested. Combined formulation also showed synergism between NSOME and PSOME against chrysanthemum aphid M. sanborni causing 100% protection compared to 68.4 and 52.9% of NSOME and PSOME respectively after 48 at 0.5% concentration. Medicinal and aromatic plants are severely affected by large number sucking pests viz. aphids, mites, scales and mealy bugs. Spider mite Tetranychus spp is a serious pest of several important crops such as cotton, brinjal, most cucurbits, roses, hibiscus, medicinal and aromatic plants and fruit crops like apple and pear (Mayer, 1974). Most of the plants are severely attacked by spider mites during summer, they form fine webbing on the under surface of leaves and feed by sucking sap. Due to feeding, affected leaves turn silvery with lot of webbing. Several pesticides are known to be effective in controlling spider (Andrade et al., 1989, Iftner and Hall, 1983; Martin et al., 1990). Use of synthetic pesticides is discouraged on medicinal and ornamental plants. Chrysanthemum, an important floricultural crop is severely affected by aphid Macrosiphoniella sanborni (Aphididae: Homoptera). Aphids gather around the terminal buds and feed on new growth, feeding causes distorted growth and leaves may be covered by honey dew which further results in sooty mould growth as a result leaves and stem appear blackish, they are also known to transmit chrysanthemum mottle virus. Neem (Azadirachta indica L.) has been effectively used in plant protection against several insect pests under laboratory conditions (Ascher et al., 1984; Schumutterer and Ascher, 1987). However, its efficacy is limited against mites. Karanj oil is known to be effective against large number of insect pests (Katole et al., 1993; Kulat et al., 1997; Hiremath et al., 1997; Rao et al., 2002). Karanj seed oil is known to contain active metabolites such as karanjin, pongamol, glabrin and pinnatin etc. Karanjin is effective against large number of insects (Mathur et al., 1990). Hence, an attempt was made to develop a synergistic formulation consisting of active metabolites of both neem and karanj that could have better efficacy against aphids and mites. MATERIALS AND METHODS Extraction: Neem oil obtained by cold press extraction of neem seeds using an oil expeller (KOMET) was vacuum filtered to remove the undesirable impurities. Liquid partitioning of oil was done by methanol and methanolic fraction was concentrated and partitioned between ethyl acetate and water to remove the impurities of gums and sugars. Ethyl acetate fraction was the concentrated under reduced pressure using a rotary evaporator. Residue thus obtained was dissolved in HPLC grade J. ent. Res., 31 (2) : 121-124 (2007) *Corresponding author's E-mail: opsidhu@rediffmail.com