01551nas a2200145 4500008004100000022004400041245009900085210006900184300001200253490000700265520104500272100001601317700001601333856005601349 2013 eng d a1175-9003 (print), 1179-352X (online)},00aPhosphorus acid for controlling Phytophthora ‘taxon Agathis’ in kauri: glasshouse trials. 0 aPhosphorus acid for controlling Phytophthora taxon Agathis in ka a242-2480 v663 a

Phytophthora taxon Agathis (PTA) is a serious problem in Auckland and Northland kauri forests. Phosphorous acid (phosphite) is a potential treatment for infected or threatened trees. In vitro tests on phosphite-amended agar showed that PTA was more sensitive to phosphite than other Phytophthora species commonly controlled by this chemical. Before progressing to forest trials, phosphite efficacy was tested on PTA-inoculated kauri seedlings in the glasshouse. Two-year-old kauri seedlings were inoculated with PTA applied directly to trunk wounds or by soil application. Phosphite was applied as a foliar spray, as a trunk injection or as a soil drench either 5 days before or 5 days after inoculation. All untreated control trees died, whether trunk- or soil-inoculated. With phosphite injection, survival was 100% following PTA soil inoculation and 67% following trunk inoculation. Foliar spray and soil drench-applied phosphite treatments were less effective than trunk injection, although some trees survived.

1 aHorner, I J1 aHough, E.G. uhttp://www.nzpps.org/nzpp_abstract.php?paper=662420