Crop Protection最新文献

Mass rearing of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) eggs is a laborious task requiring investment of time, equipment and man hour work. The use of a surrogate prey/host, as Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), easily obtained and maintain, could be an option to undertake experiments. The aim of this study was to test to what extent the eggs of E. kuehniella is a suitable surrogate host of T. absoluta eggs to test for feeding preference and intraguild interactions between Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae) and Trichogramma achaeae Nagaraja and Nagarkatti (Hymenoptera: Trichogrammatidae). Our results shows that E. kuehniella eggs is a suitable surrogate host to test for feeding preference and intraguild interactions between natural enemies, taking in consideration that i) under single diet, feeding on T. absoluta eggs is expected to be twice that on E. kuehniella, ii) whether offering T. absoluta or E. kuehniella under different ratios of parasitized vs unparasitized eggs, feeding preference was always toward non-parasitized eggs iii) in conspecific experiments with increasing density of M. pygmaeus females, the results show an overall decrease on feeding of 38.7% of E. kuehniella compared with T. absoluta eggs but experiments with T. achaeae show an overall increase in parasitism rate of 78.2% of eggs toward E. kuehniella eggs iv) in heterospecific experiments with increasing density of both natural enemies, when using E. kuehniella eggs we found an overall decrease on feeding consumption of 30% and an increase of parasitism rate of 65%.

The relationship among the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), its predator Serangium japonicum (Coleoptera: Coccinellidae), and its parasitoid Encarsia formosa (Hymenoptera: Aphelinidae) can be defined as intraguild predation (IGP). IGP represents an interaction that combines elements of both predation and competition between two species. In our previous study, predators (S. japonicum) often indirectly reduce the number of parasitoids (E. formosa) by consuming shared food resources, such as B. tabaci. To suppress whitefly outbreaks, a combination of parasitoids and predators is often released together using a mixed-species approach. However, the impact of the parasitic behavior of parasitoids on the feeding behavior of specific predators, such as S. japonicum, has not yet been well-studied. We conducted a laboratory study to examine how the parasitoid E. formosa affects the predation rates and performance of S. japonicum. Results indicate that S. japonicum shows a preference for non-parasitized whiteflies over parasitized ones, regardless of the availability of choices. Furthermore, we found a correlation between the preference for non-parasitized whiteflies and the duration of parasitization. As the developmental days of the parasitoid mummies increased, the food intake of the predatory group decreased significantly. Additionally, as the parasitoid mummy develops, S. japonicum spends more time exploring and probing the mummy before deciding whether to consume it. In summary, our study suggests that S. japonicum exhibits a significant preference for consuming non-parasitized whiteflies. Therefore, it is important to coordinate the release timing of S. japonicum and E. formosa in the biological control of B. tabaci.

Detection and identification of corn diseases are crucial for disease control, and the segmentation of corn disease leaf image is a key step to achieve this goal. However, the images of diseased leaves in real fields are usually very complex, with characteristics of irregular shapes, blurred boundaries and unsharp background, which poses great challenges to disease prevention. To address this issue, our team constructed a dataset of diseased leaves with 857 images. Additionally, this paper proposes a high-availability segmentation algorithm for corn leaves with leaf spot disease, called SEF-UNet, which uses Res-UNet as the backbone network. The algorithm references SElayer and ELA (Efficient Local Attention). Simultaneously,we implement a feature fusion network that focuses on the output of each layer. Experimental results indicate that the Mean Intersection over Union (mIOU),Mean Pixel Accuracy (mPA), Mean Precision (mPrecision), and Mean Recall (mRecall),metrics of SEF-UNet network reach 92.62%, 95.74%, 96.63% and 95.64%.We compared our proposed method with UNet, Res-UNet, PspNet, DeepLabv3+, DANet, CCNet, Segformer-b3, and SEF-UNet under the same experimental conditions. The results demonstrate that our method significantly improves the accuracy of diseased leaf image segmentation. It provides a reference method for disease monitoring, as well as a technical basis for assessing disease severity.

The whitefly, Bemisia tabaci, serves as a carrier and transmitter of the tomato leaf curl New Delhi virus (ToLCNDV) in potatoes, leading to the emergence of potato apical leaf curl disease. Among the six insecticides tested against B. tabaci, flupyradifurone resulted in the highest mortality of nymphs and adults. Three effective insecticides were then further evaluated for their ability to prevent the acquisition and transmission of ToLCNDV by B. tabaci. Utilizing qPCR techniques, we determined the amount of virus acquired by B. tabaci from virus-positive plants that had undergone prior insecticide treatment. The results revealed a significant reduction in virus levels in the whitefly's body, flupyradifurone was found to be most effective among the tested insecticides in reducing ToLCNDV acquisition. Flupyradifurone also exhibited the highest efficacy in reducing ToLCNDV transmission by B. tabaci. Experiments conducted in the glasshouse 24 h post insecticide application demonstrated the complete prevention of ToLCNDV transmission in all plants treated with flupyradifurone. In the field experiment also, flupyradifurone effectively suppressed whitefly-mediated ToLCNDV transmission for up to 14 days following insecticide application. The findings indicate that the use of flupyradifurone has the potential to manage the vector population and control associated viral disease, which is known to cause significant losses in potato crops.

Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a major invasive insect pest of maize causing severe economic losses in all major maize-growing countries. Host-plant resistance is one of the key tactics for reducing the losses caused by this pest. In the present study, maize genotypes were screened under artificial infestation to identify resistant sources to FAW and determined the pivotal morpho-biochemical traits associated with resistance. The findings revealed that four maize genotypes, namely CML 67, DMRE 63, CML 72, and CML 141, exhibited resistance to FAW. Furthermore, several morpho-biochemical traits were identified as influential factors in conferring resistance. Trichome density, leaf thickness, cob characteristics viz., cob length, cob width, husk parameters viz., husk length, husk width, number of husk layers, husk weight, and husk tightness, and yield parameters demonstrated negative correlations with leaf damage rating among the various maize genotypes. On the other hand, leaf morphology including leaf length, leaf width and plant architecture such as plant height, number of nodes per plant, and internodal distance exhibited positive correlations with leaf damage rating. Nitrogen, phosphorous, protein, total soluble sugars, and amino acids were positively correlated with leaf damage rating, while potassium, acid detergent fiber, acid detergent lignin, total phenol, and total tannin contents exhibited negative correlations. These results suggest that certain traits, including trichome density, leaf thickness, cob characteristics, husk parameters, and biochemical traits significantly contribute resistance to fall armyworm in maize. Importantly, this research is expected to facilitate the selection of FAW-resistant lines for integration into maize breeding programs, thereby contributing to sustainable maize production.

The cultivation of cardoon, Cynara cardunculus var. altilis, for multi-purpose uses has increased substantially in recent decades. However, in some cardoon growing areas, the production of achenes is threatened by several insects, especially the weevils Larinus cynarae and Larinus scolymi. Due to the lack of specific monitoring and sampling programs for these pests, the aims of this work were to test the reliability of chromotropic traps for adult Larinus spp. monitoring and to develop binomial sequential sampling plans to assess the infestation level of L. cynarae in cardoon cultivations in a Mediterranean area. Field observations were conducted in two different cardoon growing areas in Sardinia (Italy) in 2019 and 2020. Purple- and red-colored cross-vane traps, placed at 1 m and 2 m above the ground, were utilized for monitoring Larinus spp. adults, and binomial sequential sampling plans were developed for L. cynarae based on the count of egg masses on flower heads for sample sizes of 30, 40, 50, 60, and 70 flower heads. The purple traps at 2 m above the ground were effective in monitoring L. scolymi, whereas red and purple traps were ineffective in monitoring L. cynarae adults at both 1 m and 2 m above the ground. Among different binomial sampling plans, a sample size of 70 flower heads is needed to obtain reliable estimates of L. cynarae infestations at or above 25% of infested flowers. Our findings constitute a baseline for the development of an integrated pest management program for the control of Larinus spp. infestations in cardoon-growing areas in Mediterranean environment.