Beauveria fungi phylogenetic species in South Africa

In South African forestry, the Eucalyptus snout beetle, Gonipterus sp. n. 2 (Coleoptera: Curculionidae), has become an economically important invasive pest. The adults and larvae feed on leaves and cause severe damage to Eucalyptus plantations. The egg parasitoid, Anaphes nitens Girault (Hymenoptera: Mymaridae) was introduced to control Gonipterus sp. n. 2 populations, but additional biological control is necessary. Entomopathogenic fungi (EPF) can potentially be used effectively together with A. nitens, as they can target different life stages. Entomopathogenic fungi are able to infect host insects by direct contact to the insect cuticle, killing the host and sporulating on the dead insect to infect unsuspecting healthy hosts. This study focussed on the Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) species associated with Gonipterus sp. n. 2, as well as their virulence towards adult beetles. The study found that B. bassiana cryptic species diversity was present in South Africa and associated with Gonipterus sp. n. 2. The newly described species, B. namnaoensis, as well as two novel species, Beauveria sp. nov. 1 and Beauveria sp. nov. 2 formed part of the B. bassiana cryptic species complex. Beauveria pseudobassiana species were also obtained from Gonipterus sp. n. 2 cadavers. The virulence of these species was analysed in virulence trials. Inter- and intraspecies variation in virulence were observed during the trials. The most virulent strains with the lowest survival of beetles belonged to B. namnaoensis and Beauveria sp. nov. 1. The least virulent strains with the highest beetle survivals recorded were that of two Beauveria sp. nov. 2 strains and one B. pseudobassiana strain. Moderate virulence and survival were attributed to one B. bassiana, B. pseudobassiana and two remaining Beauveria sp. nov. 2 strains. Thus, the most virulent strains of the newly described species, B. namnaoensis, as well as Beauveria sp. nov. 1 and Beauveria sp. nov. 2 could be considered for Gonipterus sp. n. 2 biological control in South African forestry.

在南非林业领域，尤加利树鼻甲虫，Gonipterus sp. n. 2（鞘翅目：象甲科），已成为一种具有经济重要性的入侵性害虫。成虫和幼虫以叶片为食，对尤加利树种植园造成严重损害。卵寄生性天敌，Anaphes nitens Girault（膜翅目：小蜂科）被引入以控制Gonipterus sp. n. 2种群，但需要额外的生物防治。昆虫病原真菌（EPF）与Anaphes nitens联合使用可望有效控制，因为它们能够针对不同的生命周期阶段。昆虫病原真菌能够通过直接接触昆虫的表皮感染宿主昆虫，杀死宿主并在死虫上产孢，以感染未察觉的健康宿主。本研究聚焦于与Gonipterus sp. n. 2相关的Beauveria bassiana (Bals.-Criv.) Vuill.（子囊菌纲：肉座菌科）物种及其对成虫的致病力。研究发现，B. bassiana的隐秘物种多样性存在于南非，并与Gonipterus sp. n. 2相关。新描述的物种B. namnaoensis，以及两个新物种Beauveria sp. nov. 1和Beauveria sp. nov. 2构成了B. bassiana隐秘物种复合体的一部分。从Gonipterus sp. n. 2的尸体中亦获得了Beauveria pseudobassiana物种。这些物种的致病力在致病性试验中得到了分析。试验中观察到了种间和种内致病力的变异。具有最低甲虫存活率的最高致病菌株属于B. namnaoensis和Beauveria sp. nov. 1。记录的最高甲虫存活率的最低致病菌株分别为两个Beauveria sp. nov. 2菌株和一个B. pseudobassiana菌株。中等致病力和存活率归因于一个B. bassiana、一个B. pseudobassiana和两个剩余的Beauveria sp. nov. 2菌株。因此，新描述物种B. namnaoensis、Beauveria sp. nov. 1和Beauveria sp. nov. 2的最致病菌株可以考虑用于南非林业中Gonipterus sp. n. 2的生物防治。