Fumigant use in perennial crops can be reduced through prolonging the life of existing orchards. The longer an orchard remains healthy and productive, the less often it will be terminated, fumigated, and replanted. Two trials were conducted to determine the effectiveness of DiTera, a toxin produced by the fungus (Myrothecium verrucaria) and Nema-Q, an extract of the soap bark tree (Quillaja saponaria) for management of root-lesion (Pratylenchus vulnus) and ring (Mesocriconema xenopla) nematodes on walnuts. In the first trial, spring and fall treatments of DiTera were applied each year for four years to variety 'Chandler' scion on seedling 'Paradox' rootstock, and to own-rooted 'Chandler' trees. On 'Paradox' rootstock, both DiTera and Nema-Q increased walnut yields (P ≤ 0.05) and produced more vigorous trees (P ≤ 0.05) without significant reductions in nematode populations (P ≤ 0.05). A second trial was conducted with three rates of DiTera and four rates of Nema-Q, combinations of the two products, and an untreated control on 'Chandler' scion on 'Paradox' rootstock. The highest rate of Nema-Q (P ≤ 0.05), and a combination treatment of DiTera plus Nema-Q (P ≤ 0.05) increased trunk circumference. Several treatments showed reductions in root-lesion and ring nematodes (P ≤ 0.05). Bionematicides can improve yield, growth, and vigor in walnut orchards infested with plant-parasitic nematodes.

Easter lily bulbs for greenhouse forcing are produced in Del Norte County, California and Curry County, Oregon, USA. Pratylenchus penetrans infestation seriously affects growth of field grown bulbs. During two consecutive years of field trials containing 22 treatments, commercially prepared formulations of essential oils (EOs) were compared to an untreated control and to a standard chemical fumigant treatment (FU) (1,3-dichloropropene and metam sodium) applied preplant followed by phorate (PH) at planting to determine their value in the management of lesion nematode, and in improving plant health. The EO products Duogard, EF400, EF300, and Cinnamite were tested as preplant dips to bulblet planting stock. The treated bulblets were tested either alone, in combination with PH at-planting, at planting following FU or in combination with PH at planting following FU. The organophosphates ethoprop and fosthiazate were also tested either alone, or at a reduced rate in combination with a reduced rate of PH. With respect to bulb circumference, ten treatments consistently outperformed the control. In consecutive years, three treatments had healthier looking roots than the control. At harvest, levels of lesion nematode within roots were consistently lower in nine treatments. EOs were beneficial in mitigating nematode damage.Easter lily bulbs for greenhouse forcing are produced in Del Norte County, California and Curry County, Oregon, USA. Pratylenchus penetrans infestation seriously affects growth of field grown bulbs. During two consecutive years of field trials containing 22 treatments, commercially prepared formulations of essential oils (EOs) were compared to an untreated control and to a standard chemical fumigant treatment (FU) (1,3-dichloropropene and metam sodium) applied preplant followed by phorate (PH) at planting to determine their value in the management of lesion nematode, and in improving plant health. The EO products Duogard, EF400, EF300, and Cinnamite were tested as preplant dips to bulblet planting stock. The treated bulblets were tested either alone, in combination with PH at-planting, at planting following FU or in combination with PH at planting following FU. The organophosphates ethoprop and fosthiazate were also tested either alone, or at a reduced rate in combination with a reduced rate of PH. With respect to bulb circumference, ten treatments consistently outperformed the control. In consecutive years, three treatments had healthier looking roots than the control. At harvest, levels of lesion nematode within roots were consistently lower in nine treatments. EOs were beneficial in mitigating nematode damage.