淡紫紫孢菌YES和粉红螺旋聚孢霉67-1组合对黄瓜根结线虫病的防效评价

Efficacy of Combined Use of Purpureocillium lilacinum YES and Clonostachys rosea 67-1 in Suppressing Cucumber Root-knot Disease Caused by Meloidogyne incognita

为了提高生防菌的防病效果及其稳定性,本研究以黄瓜根结线虫病为靶标病害,对淡紫紫孢菌(原名为淡紫拟青霉)YES与粉红螺旋聚孢霉67-1混和使用的防病效果进行了评价。平板对峙实验表明两菌株相容性较好,在马铃薯和黄瓜根际分泌物培养基上无拮抗作用;通过测定两菌株对根结线虫的卵寄生性及其无菌发酵滤液对2龄幼虫致死作用,确定YES菌株孢子悬浮液(2×106孢子/m L)对根结线虫的卵寄生作用(51.0%)显著高于菌株67-1(44.0%);而菌株67-1代谢产物48 h后对根结线虫2龄幼虫的致死率(100%)高于菌株YES(77.4%)。土壤中2龄幼虫接种量为1000线虫/100 g土时,将菌剂YES和67-1单独或混和加入育苗基质中(终浓度为106孢子/g基质)并在移栽时穴施50 g菌剂(106孢子/g),结果表明两菌株单独使用和混和使用的防治效果接近,在20%~30%左右;根据blissing independence模型,两菌株之间表现为拮抗作用。土壤中线虫卵密度为398卵/100 g干土时,菌剂YES和67-1混和使用可显著抑制黄瓜根系上根结的形成,防病效果为63.7%,显著高于两菌剂单独使用的防效33.0%和41.3%。两菌株之间表现为累加效应。上述结果表明,两个主要作用机理不同的生防菌混和使用可以延缓根结线虫的侵染,提高防病效果。但土壤中线虫虫态和密度影响依据blissing independence模型判定生防菌之间的相容性。该结果对杀线虫复合生防菌剂的研制及使用技术改进具借鉴意义。

In order to improve the biocontrol efficacy of biological control agents (BCA), the authors used Purpureocillium lilacinum YES and Clonostachys rosea 67-1 in combination to control cucumber root-knot nematode caused by Meloidogyne incognita. Dual culture tests on plates of PDA and cucumber root extraction media demonstrated that the two fungi were non-antagonistic to each other. Determination of parasitized eggs in sterile 24-well cell culture plates showed that 51.0%of eggs were parasitized by YES, higher than that parasitized (44.0%) by 67-1, after inoculation with 2×106 spores per milliliter. Tests on mortality showed that 100%of J2 died after treatment with fermentation filtrates of 67-1 for 48 h, higher than that (77.4%) by filtrate of YES. The control efficacies of the two fungi alone or in combination were tested in greenhouse and field by mixing their powders with growth-medium of vegetable seedlings and hole-applying of 50 g powders at final concentration of 106 conidia/g during transplantation. Investigation of galls on the cucumber roots indicated that the control efficacy was related to the initial population of nematode eggs or juveniles inoculated in soil. At high inoculation density of J2 at 1000 J2/100 g soil, all BCA treatments could not perform good control, with efficacy only 20%-30%. According to blissing independence model, antagonistic effect was got between YES and 67-1 under this condition. While at the nematode density of 398 eggs/100 g of soil in field trail, YES and 67-1 powders in combination could significantly suppress gall numbers on cucumber root system and the control efficacy reached 63.7%, higher than single use. According to blissing independence model, additive effect was obtained for the combined use. These results suggested that combined usage of the two biocontrol agents could lead to a delay ofinfection by nematodes, but this was affected by the developmental stage and density of the nematode in soil. The results are of significance in developing complex BCA preparations and their delivery system in field.