This paper investigates 71 isolates of two genera of entomopathogens, Metarhizium and Beauveria, and a biostimulative genus Trichoderma, for their ability to infect yellow mealworms (Tenebrio molitor) and to stimulate maize (Zea mays) growth. Fungal origin, host, and isolation methods were taken into account in virulence analysis as well. Isolates Metarhizium brunneum (1154) and Beauveria bassiana (2121) showed the highest mortality (100%) against T. molitor. High virulence seems to be associated with fungi isolated from wild adult mycosed insects, meadow habitats, and Lepidopteran hosts, but due to uneven sample distribution, we cannot draw firm conclusions. Trichoderma atroviride (2882) and Trichoderma gamsii (2883) increased shoot length, three Metarhizium robertsii isolates (2691, 2693, and 2688) increased root length and two M. robertsii isolates (2146 and 2794) increased plant dry weight. Considering both criteria, the isolate M. robertsii (2693) was the best as it caused the death of 73% T. molitor larvae and also significantly increased maize root length by 24.4%. The results warrant further studies with this isolate in a tri-trophic system.

The objective of our research was to test hyperspectral imaging as a method for early detection and discrimination of biotic and abiotic stress in maize. We investigated the individual and combined effects of wireworm feeding and drought stress on leaf spectral responses and on various morphological and physiological traits of maize plants, selecting two hybrids with different tolerance to drought. Physiological parameters were determined at three time points (14, 21 and 28 days after adding wireworms and changing watering regime), along with hyperspectral imaging. Most of the differences in physiological characteristics between treatments were detected on day 21, when drought was the main cause of the negative physiological outcome, while the presence of wireworms only caused lower relative chlorophyll content, resulting in lower combined stress damage in some treatments. The morphological data showed greater wireworm damage to hybrid ZP341 and a greater negative effect of combined stress on hybrid FuturiXX. Hyperspectral imaging detected pest infestation and drought stress before they were detected by classical methods, with the highest overall accuracy on day 14 (84.7%) and the lowest on day 28 (67%). It can therefore be used as a method for early detection of wireworm infestation and/or drought in maize.