Peanut (Arachis hypogaea L.) became a major money crop planted in rotation with cotton, especially when the boll weevil was a widespread concern across the cotton belt (Beattie, 1920). Today, peanut ranks 7^th in Alabama’s agricultural commodity crops (USDA NASS, 2022). Nationally, Alabama ranks 2^nd in peanut production, with 255.8 million kilograms (3,363 kg/ha) of peanuts produced in 2024 (USDA NASS, 2025). Peanuts are a major contribution both nationally and locally to the economy, with a farm value of $1 billion across the U.S. (National Peanut Board, 2026).

Thrips (Thysanoptera: Thripidae) are a common pest in multiple crops across the Southeastern U.S., vectoring several Tospovirus diseases. Specifically in peanuts, tobacco thrips (Frankliniella fusca Hinds) vector the tomato spotted wilt virus (TSWV). Both larvae and adult thrips can transmit the virus when feeding directly on the plant, causing leaf chlorosis, curling, and yield loss (LaTora et al. 2022), especially when thrips populations are high early in the growing season (Srinivasan et al. 2018). Thrips damage appears as “silvering” on the leaves, which is a result of empty epidermal cells in leaves fed upon by thrips (Srinivasan et al. 2018). Tomato spotted wilt virus induces several symptoms on infected peanut plants, including concentric ring spots, chlorotic patterns, general stunting on plants, and also misshaped pegs and kernels (Srinivasan et al. 2017). Earlier expression of TSWV symptoms has been associated with greater yield loss compared with symptom expression later in the growing season (Culbreath et al. 1992, Garcia et al. 2000). Studies show that there is a correlation between thrips populations and TSWV incidence (Garcia et al. 2000, Shrestha et al. 2015). Research from the University of Georgia shows that for every 1% TSWV incidence in the Georgia-06G (GA-06G) variety, yield is reduced by ~22 kg per hectare (Abney, 2022).

Several management strategies, including both chemical and cultural practices, can reduce thrips injury and potentially TSWV incidence. Using pre-plant in-furrow insecticides, such as imidacloprid, phorate, and aldicarb are shown to effectively suppress thrips (Marasigan et al. 2015). However, insecticide suppression of thrips does not necessarily result in reduced TSWV incidence, and the effectiveness of chemical control may be influenced by insecticide resistance and application timing. Reduced susceptibility to neonicotinoids, including imidacloprid, has been documented in the southeastern United States (Huseth et al. 2016), potentially limiting the reliability of these products for thrips management. Marasigan et al. 2015 found that the use of alternative insecticides, including foliar applications of thiamethoxam, spinetoram and cyantraniliprole, were effective at reducing thrips feeding regardless of variety, but injury in plots treated with these alternative insecticides was no different than that of the non-treated plots. Studies show planting date reduces thrips incidence and TSWV severity (Mahoney et al. 2018, Cooke et al. 2025). Mahoney et al. (2018) observed peanuts planted late had less thrips injury. Cooke et al. (2025) found similar results, with greater thrips injury and TSWV incidence in early planted peanuts compared to late planted peanuts. Variety selection is another important cultural factor in managing TSWV. According to Wright et al. (2016), varieties differ in their resistance to diseases. Branch et al. (2003) noted that TSWV-resistant, runner-type peanut cultivars are the most important defense to control spotted wilt disease. Along with variety selection, Wright et al. (2016) also noted that higher seeding rates reduce TSWV incidence. Though thrips pressure can have a substantial impact on yield, other pests such as nematodes can also impact peanut production.

Nematodes are significant pests of peanuts in the southeast. Several Meloidogyne species are associated with peanut, with Meloidogyne arenaria (peanut root-knot nematode) being the predominate and most damaging species in Alabama (Minton and Baujard 1990, Dickson and De Waele 2005, Hagan et al. 2025). Yield losses from M. arenaria can exceed 50% in highly infested fields (Minton and Baujard, 1990). Meloidogyne arenaria juveniles infest peanut roots, pegs and pods, inducing giant cells and root galls that impair water and nutrient uptake (Jones 1981, Dickson and De Waele 2005). Above ground symptoms include stunting and premature plant death, while infected pegs may break during harvest and infected pods can reduce yield and quality (Starr and Morgan 2002). Management of M. arenaria relies primarily on crop rotation, resistant cultivars and nematicides (Grabau et al. 2020, Hagan et al. 2025). Resistant cultivars can provide a less costly alternative to nematicides and greater flexibility than crop rotation (Grabau et al. 2025). Nematicides can also increase yields under high nematode pressure (Grabau 2020). The objective of this study was to evaluate the effects of variety and insecticide treatment on thrips management in fields infested with M. arenaria.

Overall, peanuts that were treated with an at-plant insecticide were healthier, with less thrips injury and virus, ultimately producing greater yields than untreated peanuts. Both cultivar and at-plant insecticide affected yield, with GA-06G producing greater yield than GA-12Y and insecticide treated peanuts producing greater yield than non-treated peanuts. In our trials, plant populations were similar across treatments and varieties. Zurweller et al. (2023) found that planting date and variety had an impact on plant population, while insecticide treatment did not affect plant stand. Our data also indicated that non-treated peanuts had less vigor than those treated with an at-plant insecticide. However, because insecticide treatments also reduced thrips injury, the observed differences in vigor cannot be separated from the effects of thrips feeding and injury. Thus, these results should be interpreted as an overall plant response to at-plant insecticide protection rather than evidence that insecticide directly impacted plant health. Similar increases in plant vigor with at-plant insecticides have been reported by Moor et al. (2021).

Previous research documented a clear relationship between thrips abundance and TSWV incidence (Garcia et al. 2000, Shrestha et al. 2015). Although we did not directly quantify thrips populations, thrips injury ratings provide a reliable indicator of feeding activity, which is the mechanism by which TSWV is spread. We observed this correlation in our study, where non-treated peanuts had greater thrips injury (thus higher thrips activity) and correspondingly higher incidence of TSWV compared to peanuts treated with an at-plant insecticide. We also saw a reduction in TSWV in the GA-12Y variety, which aligns with the documented TSWV resistance of this cultivar (Branch et al. 2023) and with findings from Cooke et al. (2025), who reported that GA-12Y had lower incidence of TSWV than GA-06G. These results agree with research showing that peanut genotypes express tolerance rather than complete resistance to TSWV, showing less severe symptoms despite still being infested with thrips (Shrestha et al. 2013). Broader germplasm evaluations have found that genotypic differences significantly influence both thrips feeding injury and TSWV infection levels (Chen et al. 2023), supporting our interpretation that genetic background of GA-12Y contributed to reduced virus impact and improved canopy maintenance.

Fractional green canopy coverage (FGCC) was influenced by treatment and variety in our study. FGCC is affected by cumulative early-season stress and is thus influenced by plant vigor, thrips injury, and TSWV symptom expression, so reduced thrips injury from at-plant insecticides likely contributed to more rapid and complete canopy development (Funderburk et al. 1998). Similarly, GA-12Y had greater FGCC than GA-06G. However, this difference should not be solely attributed to TSWV tolerance because GA-12Y also differs from GA-06G in vegetative growth characteristics and can produce substantial vine growth. Within both cultivars, greater TSWV incidence was associated with reduced FGCC, suggesting that TSWV negatively contributed to canopy development independently of the overall cultivar difference. Thus, greater canopy coverage observed in GA-12Y likely reflects a combination of inherent cultivar growth characteristics and responses to TSWV and other early-season stresses.

Our data showed no differences in peanut root-knot nematode eggs between variety or treatment. However, previous research has shown that the nematicides tested in this study can suppress peanut root-knot nematode populations. Aldicarb has reduced populations and increased peanut yield in field studies, while oxamyl has also provided suppression of root-knot nematodes (Rodríguez-Kábana et al. 1982, Rodríguez-Kábana et al., 1985). Although treatment differences were not significant in our study, a similar numerical trend was observed, as egg densities were lower following AgLogic and Vydate. The lack of significant separation may be associated with the relatively low and variable nematode pressure during the study. Although the trial area had a history of peanut root-knot nematode infestation, nematode populations were not quantified prior to planting; therefore, initial nematode pressure could not directly be determined. Dry, drought-like conditions during the trials may have further limited nematode activity and reproduction. Soil moisture is the driver of nematode activity because nematodes rely on soil moisture for movement, feeding and host infection. Nematode abundance, biomass and activity have been shown to decline under drought conditions (Zhao et al. 2018, Zhao et al. 2024). Because environmental conditions can override management and varietal influences, drought years often mask differences among treatments, making it difficult to detect biological responses (Hajihassani et al. 2018, Nyaku et al. 2016).

Regardless of treatment, GA-06G outyielded GA-12Y by ~595 kg per ha in our study. There are varying results in the literature between the yield potential of these two varieties. Similarly, Standish et al. (2019) found that GA-06G had superior yield over GA-12Y under high fungicide input programs. However, Sidhu et al. (2019) found that GA-12Y outyielded GA-06G across multiple planting dates in a three-year study. Finally, Cooke et al. (2025) found no differences in yield between these cultivars across multiple planting dates in a two-year study. Differences in maturity between cultivars may have contributed to the yield response observed in our study. Because both cultivars were harvested at the same date, the later maturating GA-12Y may not have reached optimum maturity at harvest. Peanuts were not graded; therefore, we were unable to use grade data to further evaluate potential differences in maturity at harvest. Although TSWV incidence differed between cultivar, overall, incidence was low, and other disease and late-season insect pressure was also low. Thus, yield losses associated with insects and disease were likely minimized.

We also found a significant increase in yield for at-plant insecticide treatment. Regardless of treatment, peanuts that received an at-plant insecticide treatment yielded ~1,044 kg per ha over the non-treated check. These results are in line with other studies evaluating the impact of at-plant insecticides on yield (Cooke et al. 2025, Zurweller et al. 2023, Brandenburg et al. 2021, Mahoney et al. 2018). Overall, our results confirm that protecting seedling peanut from early thrips injury can meaningfully improve yield, even in years with minimal TSWV, emphasizing that at-plant insecticide use remains a reliable, yield-protective management practice for April planted peanuts in Alabama.