Kanetis Loukas, Förster Helga, Adaskaveg James E
Department of Plant Pathology, University of California, Riverside 92521.
Department of Plant Pathology, University of California, Davis 95616.
Plant Dis. 2008 Feb;92(2):301-310. doi: 10.1094/PDIS-92-2-0301.
For the first time in over 25 years, three new fungicides (azoxystrobin, fludioxonil, and pyrimethanil), all belonging to different chemical classes, are being registered for postharvest use against Penicillium decays of citrus fruit in the United States. Baseline sensitivities of Penicillium digitatum and P. italicum were developed using isolates collected before the commercial use of these new fungicides. In a comparison of methods, EC values obtained using the spiral gradient dilution method were very similar to those obtained using traditional agar dilutions of fungicides. For azoxystrobin, the addition of salicylhydroxamic acid (SHAM) did not significantly affect EC values for mycelial growth of both species. In additional studies on conidial germination of P. digitatum, SHAM significantly reduced EC values for azoxystrobin. For pyrimethanil, the mean EC value for mycelial growth obtained using a minimum growth medium for anilinopyrimidine fungicides was significantly lower but comparable to values obtained when using potato dextrose agar . For mycelial growth of P. digitatum, mean EC values were 0.014, 0.025, and 0.313 μg/ml, whereas for conidial germination, they were 0.074, 0.163, and 1.195 μg/ml for azoxystrobin, fludioxonil, and pyrimethanil, respectively. For P. italicum, mean EC values for mycelial growth for fludioxonil and pyrimethanil were 0.005 and 0.040 μg/ml, respectively. For azoxystrobin, the mean EC value for mycelial growth for 33 isolates was 0.029 μg/ml. Four isolates had EC values ≥0.772 μg/ml and were considered part of a resistant subpopulation. Multiple resistance between the older and new postharvest fungicide classes on citrus was not detected in P. digitatum, and all isolates that were sensitive or resistant to imazalil or thiabendazole were sensitive to the new compounds. This information is important for monitoring populations of P. digitatum, where resistance against the older fungicides has commonly developed.
25 多年来，三种新型杀菌剂（嘧菌酯、咯菌腈和嘧霉胺）首次在美国登记用于采后防治柑橘果实的青霉腐烂病，这三种杀菌剂分属于不同的化学类别。利用在这些新型杀菌剂商业化使用之前收集的分离菌株，测定了指状青霉和意大利青霉的基线敏感性。在方法比较中，采用螺旋梯度稀释法获得的 EC 值与使用传统杀菌剂琼脂稀释法获得的 EC 值非常相似。对于嘧菌酯，添加水杨羟肟酸（SHAM）对两种菌的菌丝生长 EC 值没有显著影响。在关于指状青霉分生孢子萌发的进一步研究中，SHAM 显著降低了嘧菌酯的 EC 值。对于嘧霉胺，使用苯胺嘧啶类杀菌剂的最低生长培养基获得的菌丝生长平均 EC 值显著较低，但与使用马铃薯葡萄糖琼脂时获得的值相当。对于指状青霉的菌丝生长，嘧菌酯、咯菌腈和嘧霉胺的平均 EC 值分别为 0.014、0.025 和 0.313 μg/ml，而对于分生孢子萌发，平均 EC 值分别为 0.074、0.163 和 1.195 μg/ml。对于意大利青霉，咯菌腈和嘧霉胺的菌丝生长平均 EC 值分别为 0.005 和 0.040 μg/ml。对于嘧菌酯，33 个分离菌株的菌丝生长平均 EC 值为 0.029 μg/ml。有 4 个分离菌株的 EC 值≥0.772 μg/ml，被认为是抗性亚群体的一部分。在指状青霉中未检测到柑橘采后新旧杀菌剂类别之间的多重抗性，所有对抑霉唑或噻菌灵敏感或抗性的分离菌株对新化合物均敏感。这些信息对于监测指状青霉群体很重要，因为该菌对旧杀菌剂的抗性通常已经产生。
