Pest Management Science最新文献

Background: Phoma leaf spot/stem canker is an international oilseed rape (Brassica napus) disease caused by Plenodomus lingam (Pl) and Plenodomus biglobosus (Pb). Phoma management can include fungicide applications, often sterol 14α-demethylase (CYP51) inhibitors (DMIs). Pl and Pb isolates (collected throughout Poland in 2024) were screened for in vitro sensitivity to the DMI prothioconazole-desthio, and molecular mechanisms associated with altered sensitivity were investigated.

Results: Pl isolates (2024) were less sensitive (4-fold) than older (before 2002) isolates. All Pl (2024) isolates carried CYP51 promoter inserts, likely a Sahana transposable element (TE) fragment, previously associated with CYP51 overexpression and decreased DMI sensitivity. In addition, Pb isolates with decreased DMI sensitivity were also identified, but without such TE inserts. CYP51 gene sequencing instead revealed substitution G476S that was absent in more-sensitive G476 isolates. G476S homologues have been linked to decreased DMI sensitivity in multiple other fungi. Pb G476S isolates were less sensitive (7.3-fold) than Pb G476, widespread throughout Poland, and comprised 14 of 24 (58%) Pb isolates tested. Although CYP51 promoter inserts were detected in 2 of 24 (8%) Pb isolates, these were promoter sequence duplications (not TEs) and not obviously associated with decreased sensitivity. Pl isolates carrying promoter inserts (predominant in recently tested European populations) were more sensitive (2.6-fold) than Pb G476S, but less sensitive (2.8-fold) than Pb G476.

Conclusion: We provide first evidence for a CYP51 substitution associated with decreased DMI sensitivity in Pb. Result implications for phoma management, how DMI usage might influence pathogen population structure, resistance management strategies and future research required are discussed. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

With the continual increase in detection of fungicide resistance in plant pathogens, there is an ever-growing need for management strategies to reduce the chance of resistance evolving in the field, and if it does occur, provide strategies to ensure fungicides can still be used effectively. However, the development of effective management strategies requires a thorough understanding of the epidemiology of the pathogen and how this might impact on selection of fungicide-resistant strains within a population. The blackleg pathogen, Leptosphaeria maculans, can infect canola (Brassica napus) throughout the growing season with yield loss associated with crown cankering or infection of the upper stems/branches. The disease cycle consists of infection of the plant early in the growing season, such as at the cotyledon up to the 4- to 6-leaf stage, to induce cankering on cultivars that do not carry effective plant resistance (or R) genes. Infections later in the season lead to infections of the upper stems/branches. Hence, fungicides can be applied up to four times during the season to control disease symptoms. However, it is currently unknown whether fungicide applications late in the growth of the plant will lead to selection of resistance in the population, as the pathogen would require enough time to colonise the plant and undergo sexual reproduction. Here we show that infections as late as the 30% bloom stage do indeed have sufficient time for the pathogen to grow down and colonise the base of the stem which provides the substrate to persist for the following season and undergo sexual reproduction, i.e., the next generation of inoculum. This has implications for fungicide management strategies as it means any fungicide application throughout the growing season can lead to selection of resistance. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Background: Winter oilseed rape (WOSR, Brassica napus) is a major food, feed and fuel crop that heavily relies on pesticides and fertilisers to obtain maximum yield. We tested the potential of intercropping WOSR with legumes (frost-sensitive spring faba bean, frost-sensitive berseem clover or winter hardy pea) to reduce the abundance of and damage caused by the WOSR insect pest complex, enhance biocontrol and replace synthetic inputs with ecosystem functions. Each intercrop was tested under varying crop management practices (full or reduced fertilizer and pesticide input, WOSR row spacing and sowing time of legume crop relative to WOSR).

Results: WOSR - spring faba bean intercropping reduced the abundance of cabbage stem flea beetle larvae on average from 6.87 to 3.48 per plant compared to WOSR sole cropping, but a 10-day sowing delay of the clover or spring faba bean intercrop increased cabbage stem flea beetle larvae per plant from 3.17 to 5.52 compared to when the crops were sown simultaneously. WOSR - spring faba bean intercropping also reduced pollen beetle bud damage by 34% (95% CI: 16%, 48%) compared to WOSR sole cropping. Parasitism rates of pollen beetle and cabbage seed weevil were not affected by intercropping or crop management. WOSR seed yield (kg ha^-1) was 35% (95% CI: 13%, 51%) lower in WOSR-spring faba bean intercropping compared to WOSR sole cropping, and 38% (95% CI: 26%, 47%) lower in low input compared to high input systems.

Conclusion: Our results confirmed that intercropping WOSR with frost-sensitive legumes can reduce insect pest pressure, but also highlighted a trade-off with WOSR yield and the importance of legume sowing time in relation to WOSR. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.