NOVELTY - Preparation of compost extract involves collecting waste corn stalks, crushing, adding crushed corn stalks into the empty plastic bucket, stirring, adding water until corn stalks are fully wet, pressing, filling the entire plastic bucket, sealing, carrying out anaerobic fermentation at ambient temperature, supplementing with oxygen and water, taking mature corn stover compost, placing in plastic bucket, adding water until compost is completely submerged in water, stirring, sealing lid, extracting, opening sealing cover, stirring, filtering, storing in refrigerator and using it as dope test.    USE - Method for preparing compost extract used for controlling instar larvae and egg of root-knot nematode (claimed).    ADVANTAGE - The method is environment-friendly.    DETAILED DESCRIPTION - Preparation of compost extract comprises collecting waste corn stalks, crushing, adding crushed corn stalks into the empty plastic bucket, stirring, adding water until corn stalks are fully wet, pressing, filling the entire plastic bucket, sealing, carrying out anaerobic fermentation at ambient temperature, supplementing with oxygen and water, taking mature corn stover compost, placing in plastic bucket, adding water until compost is completely submerged in water, stirring, sealing lid, extracting at room temperature, opening sealing cover, stirring, filtering using gauze to obtain corn straw compost extract, storing in refrigerator and using it as dope test. An INDEPENDENT CLAIM is included for application of compost extract comprising taking the prepared corn stalk extract liquid, placing into penicillin bottle, adding sterile water, adding intar larvae of root-knot nematodes where each vial contains 120-180 bar to obtain diluted solution, providing each treatment with four replicates, using sterile water as control, placing in constant temperature incubator at 25 plus minus 0.2 degrees C for 24 hours, 48 hours and 72 hours for each treatment, collecting samples, processing separately and computing the mortality and corrected mortality rate where mortality is calculated using formula mortality(%)=number of dead nematode/processing nematode numberx 100 and corrected mortality is calculated using formula corrected mortality(%)=(handling mortality-mortality rate control)/(1-control mortality rate)x 100.