Effect of spirotetramat and fluensulfone on population densities of Mesocriconema xenoplax and Meloidogyne incognita on peach

Management of plant-parasitic nematodes (PPNs) on peach is needed for a longer period of time than is typically afforded by pre-plant fumigant nematicides. Two post-plant nematicides, spirotetramat and fluensulfone, were evaluated for control of Meloidogyne incognita and Mesocriconema xenoplax under laboratory and greenhouse conditions. In vitro assays were conducted to test the effect of spirotetramat at 0.017 and 0.026 kg a.i./ha and fluensulfone at 3.92 kg a.i./ha on the mobility of both M. incognita and M. xenoplax in 24-well plates for 24, 48, and 72 hr, compared to a water control. Both fluensulfone and spirotetramat reduced mobility of M. xenoplax, but only fluensulfone reduced the mobility of M. incognita, compared to the untreated control. In peach greenhouse trials, both spirotetramat at 0.017 kg a.i./ha and fluensulfone at 3.92 kg a.i./ha reduced M. incognita numbers by 62 and 77% at 40 d after inoculation (DAI), respectively; neither chemical reduced populations at 70 DAI. Fluensulfone reduced M. xenoplax numbers by 84, 94, and 96% at 30, 60, and 90 DAI, respectively. No effects were observed for spirotetramat on M. xenoplax. At 40 DAI, dual applications of spirotetramat 30 d apart reduced M. incognita numbers by 58 and 54% for both 0.017 and 0.026 kg a.i./ha rates, respectively; no reductions were observed at 70 DAI. No effect was seen for a dual application of spirotetramat on M. xenoplax. These post-plant nematicides may provide additional options for management of PPNs on peach.