Inter-efficacy effects of Velum, Biocult and Nemafric-BL phytonematicide on the suppression of Meloidogyne enterolobii in potato under field conditions

Potato (Solanum tuberosum L.) does not have genotypes that are resistant to the root-knot (Meloidogyne species) nematodes and thus, were effectively managed using fumigant synthetic chemical nematicides. Since the withdrawal of the products from the agrochemical markets due to their environment-unfriendliness, Meloidogyne enterolobii (Yang and Eisenback) has emerged as a serious threat in crop rotation systems intended to manage this pest. A wide range of alternative products, viewed as being environment-friendly, are being investigated against Meloidogyne species on various crops, but with limited inter-efficacy comparisons. Thus, it was against the stated backdrop that an experiment was carried out to investigate the inter-efficacy comparison of Velum (a.i., fluopyram), Biocult (a.i. Glomus + Trichoderma spp.) and Nemafric-BL phytonematicide (a.i., cucurbitacin B) on the suppression of M. enterolobii in potato under field conditions. The initial nematode population density (Pi) averaged 13 J2/250 ml soil subsample, therefore necessitating augmentation with 100 eggs + J2 M. enterolobii in the furrow with potato tubers, with each treatment applied according to label instruction around randomly selected potato tubers, prior to covering with soil. At harvest, the treatments had significant (P ≤ 0.05) effects on eggs in root, juveniles in root and reproductive potential (RP), contributing 88, 73 and 93% in total treatment variation of the respective variables. Relative to untreated control, Velum reduced eggs in root, juveniles in root and RP by 100 38 and 62%, respectively. Biocult reduced the respective variables by 42, 37 and 71%. Similarly, Nemarioc-BL phytonematicide reduced the respective variables by 67, 70 and 48%. Although inter-efficacy variation in eggs and juveniles in root was significant (P less than 0.05), such variation was not significant on reproductive potential, with all test products significantly reducing nematode variables when compared to untreated control. In conclusion, Velum, Biocult and Nemafric-BL phytonematicide had comparable inter-efficacy effects on the suppression of M. enterolobii in potato and each product could be used in the management of nematode population densities in potato under field conditions.