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Plant pesticide residues,such as chinaberry(Melia toosendan)residue and sand cypress(Sabina vulgaris)residue,are pesticidal plant materials discarded after the bioactive ingredient has been extracted with organic solvents.The only option for botanical pesticide residue utilization has been as landfill.Chinaberry residue(CBR)and sand cypress residue(SCR)were collected and composted in Yangling,Shaanxi Province,China.We studied the effects of chinaberry residue compost(CBRC),CBRC incorporated with Trichoderma viride(CBRCT),sand cypress residue compost(SCRC),and SCRC incorporated with T.viride(SCRCT)on the root-knot nematode,Meloidogyne incognita,infesting the balloonflower(Platycodon grandiflorum).Bioassay results indicated that stock solutions of the CBRCT and SCRCT extracts significantly inhibited egg hatching and caused high larval mortality,followed in degree by the CBRC and SCRC extracts.The CBR and SCR extracts caused very low inhibition of eggs and larvae.Supplementing potting mixtures with these four composts reduced the severity of root galling and increased the proportion of marketable roots.The severity of root galling decreased and the average weight of the marketable roots increased with an increase in all the composts when supplemented at rates from 5 to 30%.CBR- and SCR-supplemented pot soils also inhibited the nematodes,but CBR and SCR applied to the soil had a phytotoxic effect and inhibited balloonflower growth.Supplementing field soil with the composts reduced the severity of root galling and the populations of southern root-knot nematodes in the soil.CBRCT and SCRCT clearly enhanced the average weight of the marketable roots by 30.45 and 26.64%,respectively.Continuous supplementation with CBRCT or SCRCT in the same field significantly enhanced the control of the root-knot nematode,and the populations of nematodes continued to decrease with second inoculations.The populations of total Trichoderma spp.were distinctly enhanced and were maintained at high levels for a long time in the supplemented soils.