High tunnels are passively heated and cooled structures used for specialty crop production that can increase marketable yields, extend the growing season, and protect crops from harsh weather. Kentucky has more than 1,500 high tunnels and although there are many benefits, production still has several challenges. High soil temperatures, lack of rotation and sanitation, and intensive and continuous cropping make high tunnels hospitable environments for root-knot nematode (RKN; Meloidogyne spp.). Root-knot nematodes are one of the most economically important plant-parasites and most destructive agricultural pests worldwide. They infect over 3,000 species of crops. This plant-parasite infects roots, causing chlorosis, wilting, stunting, and yield loss. Determining the presence, population density, and species of RKN is important to help provide accurate and appropriate management strategies for growers. Many vegetables crops, including tomato (Solanum lycopersicum L.), are hosts for RKN (Ahmad et al. 2021) including those most commonly produced in high tunnels (Janke et al. 2017). Previous research conducted in Kentucky high tunnels has observed near complete tomato crop loss due to RKN infestations (Bajek and Rudolph 2023). 

From 2019 to 2022, the Rudolph lab sampled the soil in 175 commercial high tunnels in 62 counties. Of the soil samples collected, 45% had no presence of RKN. Out of 55% of total samples that had RKN identified, 55% were identified as M. incognita, 39% M. hapla, and 4% M. arenaria. Prior to this work, there was no information regarding the presence or distribution of plant-parasite in Kentucky. Additionally, the high tunnel growers were also surveyed. Growers were asked general farm operation questions along with what they currently know about RKN, if they were aware of it on their farm, and the top management strategies they would be most willing to try. A total of 72 growers completed the survey. Though 94% of respondents were aware that RKN can cause damage, many had limited knowledge of RKN beyond that. Fifty-one percent of respondents had been farming for over 20 years, 79% grew less than five acres of vegetables, and 55% grew conventionally. When asked if they thought RKN was present on their farm, 13% of respondents indicated “Yes,” but 45% of those respondents had not taken any action to manage RKN. Cover cropping, non-host crop rotation, and soil solarization were the top RKN management strategies that growers indicated they would be most willing to try. All growers who participated in the soil survey were notified of the results of the soil sampling on their farm and whether RKN was identified. Growers and county agents were provided species specific resources and management recommendations. 

Grower preferences and demographics will influence future research directions for management of RKN in Kentucky high tunnels. With over half of the sampled high tunnels infested with RKN, this project justifies further research for management strategies for RKN, especially those that are sustainable species-specific options and appropriate for commercial high tunnels. As a result of these surveys, RKN was not only identified across the state, but growers and county agents were also educated about this important plant-parasite. This information could lead to thousands of dollars being saved on each farm through improved RKN management and prevention.

Literature Cited

Ahmad G, Khan A, Khan AA, Ali A, Mohhamad HI. 2021. Biological control: a novel strategy for the control of the plant parasitic nematodes. Antonie van Leeuwenhoek. 144(7):885–912. https://doi.org/10.1007/s10482-021-01577-9.

Bajek V, Rudolph RE. 2023. Managing southern root-knot nematode in Kentucky high tunnels using grafted tomato. HortScience 58(6):704-713. https://doi.org/10.21273/HORTSCI17141-23 

Janke RR, Altamimi ME, Khan M. 2017. The use of high tunnels to produce fruit and vegetable crops in North America. Agr Sci. 8(7):692-715. https://doi.org/10.4236/as.2017.87052.