Effect of oomatistatic Compounds and biological control agents on prodcuction of inoculum and root colonization of plants infected with Phytophthora ramorum

Abstract

In this study, viburnum (Viburnum) cuttings were treated with oomatistats (Subdue Maxx®, Banol®, and Aliette®) at standard rates for use as soil drenches or with biological control organisms (Streptomyces lydicus formulated as Actinovate SP® and used as a soil drench, and Trichoderma asperellum formulated in wheat bran and used as a top dressing) 4 days after roots were infected with Phytophthora ramorum. The amount of inoculum in runoff samples taken weekly for 5 weeks was studied using a quantitative assay analyzed as a mixed model regression and the percent colonization of roots at the end of each experiment analyzed by a general linear model. Experiments were run three times for each compound or biological control agent, except for Trichoderma, which was run twice. Root-infected viburnum cuttings treated with Banol® did not show any reduction in inoculum production compared to non-treated cuttings, and there was no significant difference in root colonization at the end of the experiment. Aliette®-treated viburnum cuttings gave off significantly less inoculum than non-treated plants at all sampling dates (days 7, 14, 21, 28, and 35; p < 0.02-0.0001), and root colonization was significantly reduced (p < 0.01). subdue maxx® significantly reduced inoculum at all sampling dates (p < 0.02-0.0001) and reduced root colonization (p < 0.0001). when actinovate sp®was applied as a soil drench to root-infected cuttings, significantly less inoculum was released than from non-treated ones at all sampling dates (p < 0.002-0.0001), and root colonization was reduced (p < 0.05). when T. asperellum in wheat bran was applied as a top dressing to pots containing root-infected cuttings, runoff contained significantly less inoculum than non-treated plants at all sampling dates (p < 0.0001), and root colonization was reduced (p < 0.0001). These results suggest that biological control agents are as effective as Subdue Maxx® and Aliette® at reducing inoculum production and root colonization in experiments lasting 35 days and are more effective than Banol®.

Parent Publication

• Proceedings of the sudden oak death fifth science symposium

Citation

Shishkoff, Nina. 2013. Effect of oomatistatic Compounds and biological control agents on prodcuction of inoculum and root colonization of plants infected with Phytophthora ramorum. In: Frankel, S.J.; Kliejunas, J.T.; Palmieri, K.M.; Alexander, J.M. tech. coords. Proceedings of the sudden oak death fifth science symposium. Gen. Tech. Rep. PSW-GTR-243. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: p. 54.