The common pine sawfly, Diprion pini (Linnaeus, 1758) (Hymenoptera: Diprionidae), is a well-known defoliating pest of various pine forests almost all over the world, including Europe. It can cause damage to many pine species but usually opts for Pinus sylvestris Linnaeus and P. nigra subsp. laricio (Poiret) Maire. The prohibition of the use of chemical insecticides in forests (at least for T & uuml;rkiye) has led to the fact that other control methods have come to the fore in the control of this pest. In this respect, biological control agents, which are eco-friendly and can persist in the field over time, providing long-term control for plant protection, have an important potential in the control of D. pini. Therefore, in this study, entomopathogenic fungi were isolated from pine forest soils and identified by gene sequencing and phylogenetic analysis. Ten isolates (DP-37, DP-38, DP-45, DP-46, DP-49, DP-53, DP-54, DP-57, DP-58 and DP-63) were identified as Beauveria pseudobassiana, four isolates (DP-35, DP-41, DP-52, and DP-61) were identified as B. bassiana, and only one isolate was identified as Metarhizium robertsii (DP-15). All isolates were tested against the larvae of the pest under laboratory conditions, and the highest mortality and mycosis values (96.6% and 63.3%, respectively) were obtained from B. pseudobassiana DP-57. This isolate was also tested against the pest under outdoor conditions using different conidial concentrations. Based on probit analysis, the LC50 and LC90 values were estimated to be 1.309 x 107 and 1.21 x 1010 conidia/ml, respectively. The results showed that B. pseudobassiana DP-57 could be a good candidate in the biological control of D. pini.

The large pine weevil (Hylobius abietis L.) is a major pest in European and Asian coniferous forests, particularly in managed plantations where clear-felling practices create ideal conditions for its population growth. Traditional management practices involving synthetic insecticides have limited efficacy in terms of reducing pest populations and pose environmental risks. This study evaluated the effectiveness of a wild entomopathogenic fungus (EPF) and the commercial entomopathogenic nematode Steinernema carpocapsae (EPN) as biological control agents (BCAs) against H. abietis in clear-felled spruce plantations in Wales and Scotland. Field trials used a randomised block design with three treatments (EPN full dose, EPF full dose and a combination of EPF+EPN at half doses each) compared to a control. Emergence trapping and destructive sampling were employed to assess treatment efficacy. All treatments significantly reduced weevil emergence, with the mixed treatment showing the greatest impact. Destructive sampling revealed strong associations between treatment type and infection outcomes in H. abietis, with a small but significant relationship between weevil developmental stages and infection types. Importantly, the treatments had no significant impact on the total abundance or taxon richness of non-target invertebrates. These findings suggest that wild EPFs alone and combined with EPNs are effective and environmentally safe alternatives to synthetic insecticides for managing H. abietis populations in managed forests.

Insect pests are serious threats to agriculture, forestry, and human health because they damage crops and trees and spread diseases. Chemical insecticides control insect pests quickly and effectively, protecting crops. Environmental and health concerns arise from their use. Long-term exposure can cause pesticide-resistant insects, requiring stronger chemicals. Beneficial insects and wildlife may be harmed. Some chemical insecticides persist in the environment, causing long-term ecological damage. The present study was to isolate, identify, and characterize entomopathogenic fungi from the soil, evaluate their pathogenicity against major insect species, and evaluate the non-target effect on soil bioindicator species. Bioassay results show that Beauveria bassiana conidia are more pathogenic to all three species at 10 days after treatment, causing 100% mortality in Halyomorpha halys and Tenebrio molitor within 10 days. The lethal concentration showed lower LC50 values of 9.5 x 103 conidia/mL in H. halys, 2.6 x 103 conidia/mL in T. molitor, and 8.3x104 conidia/mL in P. japonica, B. bassiana treatment results showed a shortened insect life time LT50 of H. halys (6.0 days), T. molitor (5.3 days), and P. japonica (6.9 days). The present study concluded that B. bassiana fungi conidia are more efficient against three major insect pests.

Tenebrio molitor L., also known as the mealworm, is a polyphagous insect pest that infests various stored grains worldwide. Both the adult and larval stages can cause significant damage to stored grains. The present study focused on isolating entomopathogenic fungi from an infected larval cadaver under environmental conditions. Fungal pathogenicity was tested on T. molitor larvae and pupae for 12 days. Entomopathogenic fungi were identified using biotechnological methods based on their morphology and the sequence of their nuclear ribosomal internal transcribed spacer (ITS). The results of the insecticidal activity indicate that the virulence of fungi varies between the larval and pupal stages. In comparison to the larval stage, the pupal stage is highly susceptible to Metarhizium rileyi, exhibiting 100% mortality rates after 12 days (lethal concentration 50 [LC50] = 7.8 x 10(6) and lethal concentration 90 (LC90) = 2.1 x 10(13) conidia/mL), whereas larvae showed 92% mortality rates at 12 days posttreatment (LC50 = 1.0 x 10(6) and LC90 = 3.0 x 10(9) conidia/mL). The enzymatic analyses revealed a significant increase in the levels of the insect enzymes superoxide dismutase (4.76-10.5 mg(-1)) and glutathione S-transferase (0.46-6.53 mg(-1)) 3 days after exposure to M. rileyi conidia (1.5 x 10(5) conidia/mL) compared to the control group. The findings clearly show that M. rileyi is an environmentally friendly and effective microbial agent for controlling the larvae and pupae of T. molitor.

Ectropis grisescens is a notorious pest in tea plantations. The control of E. grisescens relies on synesthetic pesticides but the resurgence is always accompanied by increasing resistance. Therefore, it is crucial to use biological control to reduce the damage caused by E. grisescens. Here, we collected soil from a tea plantation, used Galleria mellonella as a bait insect and successfully isolated one entomopathogenic fungus. The isolated colony was initially identified as Cordyceps sp. using morphological observation. ITS-rDNA sequence amplification and sequencing, molecular database comparisons, and phylogenetic analysis proved this fungus as a new species and thus named Cordyceps sp. WZFW1. Further virulence test of Cordyceps sp. WZFW1 against E. grisescens was evaluated under laboratory conditions. Lethal concentration was 5.74 x 10(6) spore/mL with a confidence level of 2.32 x 10(6) similar to 1.79 x 10(7) and lethal time was 2.98 days at 10(6) spore/mL and 7.47 days at 10(7) spore/mL, indicating Cordyceps sp. WZFW1 was effective at controlling E. grisescens. Our findings are significant as they contribute to the application of new entomopathogenic fungi (EPF) species as biocontrol agents, promoting eco-friendly pest management practices.

Simple Summary: Microbial pest control offers promising opportunities to develop sustainable alternatives to synthetic chemical insecticides. In Brazil, the selection of native strains of entomopathogenic fungi suggests an option for South American palm weevil (Rhynchophorus palmarum, SAPW) management and potential tools for red palm weevil (R. ferrugineus, RPW) management. Both weevils in America are susceptible to the native isolates of Beauveria bassiana, CVAD01, CVAD02, CVAD06, and CPATC/032, which originate from palm orchard soils and infected SAPW adults in northwestern Brazil's Alagoas state. The SAPW mortality rates in our study were 90 and 100% on day 21, suggesting the efficacy of these strains that are well-adapted to the environment and to the pest. We suggest both the development of formulates for microbiological insecticides against R. palmarum and future tests on R. ferrugineus. Both palm weevils, the South American (Rhynchophorus palmarum) (SAPW) and the red palm weevil (R. ferrugineus, RPW), are present in South America, affecting commercial, ornamental, and native palms. These pests oviposit and thrive on selected Arecaceae. R. palmarum mainly infests coconut (Cocos nucifera), oil palms (Elaeis guineensis), and other ornamental and native palms in America, causing a significant social impact on growers. The weevils fulfill a significant ectosymbiotic macro- and microorganism role in the first period of larval development, worsening the damage which, during this period, is not yet apparent. Palm protection in the Brazilian context suggests the use of indigenous agents for microbiological biocontrol. This research identifies three Brazilian Beauveria bassiana isolates: CVAD01, CVAD02, and CVAD06. The results suggest that the strain's impact on R. palmarum can also be compared with that of the commercial strain Beauveria bassiana. Phylogenetic analysis allowed the delimitation of species of Beauveria (Hypocreales). Pathogenicity tests caused significant mortality in R. palmarum. The isolates CVAD01, CVAD02, and CVADO6 showed high pathogenicity between 7 and 21 days, with mortality rates between 90 and 100%, suggesting that they may be effective biological control agents of R. palmarum in the field when used, within available means, to mitigate the impact of R. palmarum and R. ferrugineus in South America.