Soybean oil delays peach tree flowering, thins fruit, and kills key arthropod pests of deciduous fruit trees

Soybean oil delays peach tree flowering, thins fruit, and kills key arthropod pests of deciduous fruit trees

Beattie, G.A.C. Book author
Watson, D.M. Book author
Stevens, M.L. Book author
Rae, D.J. Book author
Spooner-Hart, R.N. Book author

Sydney, NSW University of Western Sydney Australia

2002

p.410-418

SB952.O4B4

Research at the University of Tennessee showed that spraying emulsified soybean (Glycine max (L.) Merr. [Fabales: Fabaceae]) oil on peach (Prunus persica (L.) Batsch) [Rosales: Rosaceae]) trees in late winter interfered with the escape of respiratory CO2 from shoots and increased internal CO2 concentrations in shoots for up to 8 d. Respiration rates, relative to controls, were decreased for 8 d following treatment, which indicates a feedback inhibition of respiration by the elevated CO2, Flower bud development was delayed by treatment of trees with 5% (v/v) soybean oil. Trees treated with 10% soybean oil bloomed up to 6 d later than untreated trees. Sprays also caused dose-related bud damage and thus acted as a peach fruit thinner. These effects of soybean oil may benefit growers. Delaying flowering reduces detrimental exposure to freezes, and hand - thinning of peaches is a major production cost. Research also showed that late winter sprays of soybean oil can control European red mite (ERM; Panonychus ulmi (Koch) (Acari: Tetranychidae1) and 3 scales San Jose scale (Quadraspidiotus perniciosus (Comstock)), white peach scale (Pseudaulacaspis pentagona (TargioniTozzetti) [Hemiptera: Diaspididae]), and terrapin scale (Mesolecanium nigrofasciatum (Pergande) [Hemiptera: Coccidae] )-on peach and apple (Malus x domestica Borkh. [Rosales: Rosaceae]). In field tests, > 95% mortality of the scales was recorded after application of 5% soybean oil emulsions. In other experiments, application of soybean oil sprays to apple trees during dormancy in early spring (late February and March) and in summer to foliage effectively reduced populations of ERM, and application of summer foliar sprays to apple trees controlled Aphis spp., including spiraea aphid (A. spiraecola Patch [Hemiptera: Aphididae]). Mites are especially difficult to control because they can rapidly develop resistance to synthetic miticides. Oils are especially attractive as insecticides and miticides because they are the only widely used class of pesticides to which insects or mites have not developed resistance.

Spray oils beyond 2000; sustainable pest and disease management; Proceedings of a

Research > Conference Papers