Insect population may reach pest status if the preventive steps were not taken in time, changes in weather conditions and insects coming from neighboring farmers fields. In these situations based on the field observations farmers can take up spraying botanical extracts and natural preparations (Green sprays) instead of chemical pesticides. There are wide ranges of these preparations which are evolved by the farmers (CSA, 2007).
These preparations can be classified into four categories based on how they are prepared.
6.a Aqueous or solvent extracts: for example, Neem Seed Kernal Extract is very effective against many pests. There is a wide variation in the way these extraction is prepared. For extracting ‘Allenin’ from garlic kerosene is used as a solvent. After extraction this solution is mixed with chilli extract and used against sucking pests (Prakash and Rao 1997, Vijayalakshmi et.al 1999, Prasad and Rao 2007).
6.b. Decoctions: for example, plants like tobacco, Nux Vomica etc contain volatile compounds which can be extracted by boiling them in water to get the decoction. Several decoctions are used in pest management (Prakash and Rao, 1997, Vijayalakshmi et.al, 1999, Prasad and Rao, 2007).
6.c. Concoctions: concoctions are mixtures. For example, five leaves mixture which is a aqueous extract of any five latex producing leaves is used to control pests in Tamil Nadu and other parts of south India (Prakash and Rao, 1997, Vijayalakshmi et.al, 1999, Prasad and Rao, 2007).
6.d. Microbial Solutions (Fermented products): products made by fermenting the different botanicals with animal dung and urine. These products have rich microbial cultures which help in providing plant nutrients and improving soil fertility in addition to acting as pest repellents and pest control sprays. For example cow dung urine-asafetida solution is used to manage Rice blast (Prakash and Rao, 1997, Vijayalakshmi et.al, 1999, Prasad and Rao, 2007). Read more…