D Amico, M. | Search bioRxiv

bioRxiv2025

Control of fall armyworm with Spodoptera frugiperda multiple nucleopolyhedrovirus in sweet corn cultivated under agroecological conditions

The fall armyworm (FAW), Spodoptera frugiperda (JE Smith) is a polyphagous pest documented on more than 80 plant species. In vegetable production systems, sweet corn is their preferred host, but also infests other plants such as chilli, tomato, pumpkins, cucumber, beans and eggplant. Control strategies are commonly carried out by the use of chemical insecticides even though resistance of S. frugiperda populations to several insecticides has been reported. Last decades, have registered rapid adoption of organic and agroecological practices in horticulture, particularly those that rely on bioinputs such as biopesticides and biofertilizers. The baculovirus Spodoptera frugiperda Multiple Nucleopolyhedrovirus (SfMNPV) is a pathogenic agent for the fall armyworm and an alternative tool used for its control in sustainable pest management strategies. In this work, we evaluate two indigenous SfMNPV-based liquid formulations sprayed on sweet corn cultivated under agroecological conditions. Larvae fed with leaves treated with SfMNPV OBs showed mortality rates ranging from 55 to 68 %. Offspring from adult surviving to OBs treatments was analyzed by PCR and the results confirmed sublethal infections and vertical transmission in the fall armyworm. Corn ears harvested from each treatment were individually observed for insect presence, where the lowest rate of fall armyworm per corn ear was registered in plants treated with SfMNPV OBs. Analysis of secondary plagues in corn ears identified the sap beetle Carpophilus dimidiatus and the maize-infesting fly larvae Euxesta mazorca as the most abundant insect pests. These results show that indigenous isolates of SfMNPV produce a significant control on FAW under agroecological conditions, suggesting that the use of formulations including this virus might be a valuable tool for pest management in sustainable vegetable production systems. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/666974v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@12e8d59org.highwire.dtl.DTLVardef@1420401org.highwire.dtl.DTLVardef@11516b7org.highwire.dtl.DTLVardef@186750b_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2022

Road encroachment mediates species occupancy, trait filtering and dissimilarity of songbird communities

Assessing the road effects on biodiversity is challenging because impacts may depend on both wildlife responses to roads and on the spatial arrangement of roads. We questioned whether an increase in road encroachment i.e., the advancement of roads into non-urban areas, leads to significant changes (positive and negative) in species occurrence, and if so, whether those changes are linked to specific traits related to perturbation sensitiveness, therefore acting as filters that increase the community compositional dissimilarity. Using a large citizen-science dataset of point-counts performed throughout Iberian Peninsula (4,459 unique survey sites), we modelled the effect of road density on the occurrence of common songbirds (n=58), while accounting for potential confounding effects of environment and survey effort. We then tested if species occurrence patterns would be linked to specific traits related to the ability to cope with human presence. Finally, we assessed how road density affect the community compositional dissimilarity. We estimated 24 (41%) and 12 (21%) species to be negatively and positively affected by roads, respectively. Increased road encroachment was positively related with a higher prevalence of urban dwellers and negatively related with the occurrence of species nesting and foraging on the ground. Furthermore, increasing road density translated into an increasing community compositional dissimilarity, mostly due to species turnover. Our study support previous research showing that roads have different effects on the occurrence of different species, but we revealed that at least three species' traits have a clear relation with such road responses. Such trait filtering is probably causing a high species turnover between songbird communities occurring in roaded and nearby roadless areas. Overall, we found that different species-specific responses to roads translates into changes at the community level. Landscape and road-network management should be conceived acknowledging that roads are contributing to biodiversity changes. As so, building upon the concepts of Land Sharing / Land Sparing, conservation actions should be tailored according to the different species responses e.g., road verge management targeting species having a positive relation with road density; and compensation actions targeting species showing a negative response toward roads.

ecology↗