John T. Trumble

Soil contamination by cadmium (Cd) poses an increasing threat to agricultural ecosystems and may disrupt biological pest control mediated by natural enemies. However, the multigenerational effects of Cd stress on parasitoid reproductive strategies and performance, particularly in species with contrasting ovigeny syndromes, remain poorly understood. Here, we compared the short-term (F1) and long-term (F5) effects of host-mediated Cd exposure on the synovigenic Trichogramma cacoeciae and the proovigenic T. dendrolimi. Cadmium exposure did not shift the core oviposition rhythm of either species, demonstrating that ovigeny syndrome represents a canalized life-history trait robust to multigenerational heavy metal stress. For the synovigenic species T. cacoeciae, F1 Cd exposure extended female lifespan and elevated lifetime parasitism, consistent with a hormetic stress response; by contrast, continuous Cd exposure across 5 generations (F5) suppressed early-age oviposition and total reproductive output, reflecting cumulative physiological fitness costs. In contrast, T. dendrolimi showed no significant changes in survival, daily parasitism pattern, emergence rate, or percentage of female progeny under Cd stress, except for a reduction in total parasitism after F5 exposure. These findings demonstrate that synovigenic species exhibit greater plasticity and stage-dependent responses to transgenerational Cd stress, whereas proovigenic species appear more robust. Our results provide empirical evidence for how heavy metal pollution influences parasitoid life-history traits and fitness across generations, and offer practical guidance for selecting resilient biological control agents in Cd-contaminated agricultural landscapes.

The increased basic knowledge of biological control agents’ bio‐ecology under environmental stress provides useful information for optimizing integrated pest management. With an increasing awareness of cadmium (Cd) pollution in agroecosystems, this study evaluated the transgenerational effects and host preference of two widely distributed and utilized egg parasitoids, Trichogramma dendrolimi and Trichogramma japonicum through bottom‐up effects mediated by Cd. The host rice moth Corcyra cephalonica was reared on a diet with 20 mg/kg Cd exposure for 1 generation; eggs were collected, and then exposed to Trichogramma. The survival rate, longevity, daily number of parasitized eggs, and fecundity of second generation (F1) females, emergence rate, and female adult proportion of the third generation (F2) were tested. After emerging from Cd‐exposed hosts, the survival rate and longevity of F1 T. dendrolimi female adults were significantly increased, but the daily number of eggs parasitized by, and fecundity of, F1 T. japonicum were significantly decreased. Cd exposure significantly resulted in a preference for hosts exposed to Cd in both F1 T. dendrolimi and T. japonicum, whereas no such host preference was observed when the first generation (F0) parasitoids were not exposed to Cd during their development. Our study shows the transgenerational effects and host preference on natural enemies under heavy metal exposure stress in a species‐specific way. This highlights the potential synergetic effects of heavy metal contamination on biological control. Specifically, the release of T. dendrolimi, rather than T. japonicum, should be favored at Cd‐contaminated sites, where T. dendrolimi is a more suitable biocontrol agent.

Significance: Citrus Huanglongbing (HLB) is the most destructive citrus disease worldwide and has caused billions of dollars in annual production losses, threatening the entire citrus industry. Despite extensive research efforts, there are still no effective management tools to treat HLB-positive trees or to prevent new infections. Current HLB management strategies include chemical application of insecticides and traditional heat-sensitive antibiotics, which pose threats to humans, animal health, and the environment, and likely generate drug resistant insects and microbes. Here, we identified a novel class of stable antimicrobial peptides (SAMPs) from Australian finger lime and other HLB-tolerant citrus close relatives, which has dual functions of inhibiting C Las growth in HLB-positive trees and activating host immunity to prevent new infections.

Acylsugars have been shown to provide activity against numerous insect pests of tomatoes. Comparison of acylsugar levels in four tomato plant lines, FA7/AS, FA2/AS, CU071026, and ‘Yellow Pear’, found that the acylsugar contents in the elevated acylsugar lines were significantly higher than the commercial Yellow Pear (control) tomato plant line. Adult choice tests indicated that the tomato psyllid, Bactericera cockerelli, preferred to settle on the Yellow Pear and FA2/AS lines over the line with the highest content of acylsugars, FA7/AS, and the parental line, CU071026. The no-choice test demonstrated that adults laid fewer eggs on the high acylsugar tomato lines than on the control tomato line, Yellow Pear. For all high acylsugar lines, the relative growth index of the psyllid was significantly lower compared with the commercial line, indicating a reduced potential for population growth. Although some tomato psyllids completed their life cycle on the high acylsugar tomato plant lines, the percent survival of psyllids to the adult stage when developing on the high acylsugar lines was significantly less (range = 43.7–57.1%) than on the commercial tomato line (83.8%). All mortality occurred during the early stages of development (egg stage to third instar), which has implications for acquisition and transmission of Candidatus Liberibacter solanacearum, the causal agent of tomato vein greening disease. Therefore, with reduced attractiveness for tomato psyllids and significantly reduced survival, the high-acylsugar tomato plant lines have the potential to be part of an integrated pest management program for this pest.

Many countries are utilizing reclaimed wastewater for agriculture because drought, rising temperatures, and expanding human populations are increasing water demands. Unfortunately, wastewater often contains biologically active, pseudopersistent pharmaceuticals, even after treatment. Runoff from farms and output from wastewater treatment plants also contribute high concentrations of pharmaceuticals to the environment. This study assessed the effects of common pharmaceuticals on an agricultural pest, Trichoplusia ni (Lepidoptera: Noctuidae). Larvae were reared on artificial diets spiked with contaminants of emerging concern (CECs) at environmentally relevant concentrations. Trichoplusia ni showed increased developmental time and mortality when reared on artificial diets containing antibiotics, hormones, or a mixture of contaminants. Mortality was also increased when T. ni were reared on tomatoes grown hydroponically with the same concentrations of antibiotics. The antibiotic-treated plants translocated ciprofloxacin through their tissues to roots, shoots, and leaves. Microbial communities of T. ni changed substantially between developmental stages and when exposed to CECs in their diets. Our results suggest that use of reclaimed wastewater for irrigation of crops can affect the developmental biology and microbial communities of an insect of agricultural importance.

To determine the effect of insecticides on pepper insect control, seedlings were transplanted in a sandy loam type soil on 6 Jun at the University of California’s South Coast Research and Extension Center. Experimental plots were 3 rows wide (5-ft centers) by 20 ft long and separated by a 3-ft buffer. The pepper transplants were drip irrigated (water pH 7.2–7.5). Treatments were replicated 4 times in an RCB block design. A treatment list is shown in Table 1. The Minecto Pro SC, Radiant SC, Radiant SC and Sequoia 2SC, VST-06330 EP and BeetleGone! Bt, and Asana XL EC treatments were applied as weekly foliar sprays on (1, 8, 17, 24 Aug, and 2, 9 Sep). Verimark SC was applied once as a soil drench on 8 Aug as part of the rotation, which included Radiant SC (1, 24 Aug, and 9 Sep) and Sequoia 2SC (8 Aug and 2 Sep). Pyganic 5EC was applied (24 Aug) as part of the foliar spray rotations with Trilogy EC (1 and 24 Aug), Mycotrol O (8, 17 Aug, and 2 Sep), and Entrust SC (8, 17 Aug, and 2, 9 Sep). All applications were made at twilight. A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks, ^#25 cores, and 50 mesh screens. Operating pressure was 110 psi delivering 100 gpa. The treatment, which consisted of Pyrellin 5EC, Trilogy EC, Mycotrol O, and Entrust SC, did not use an adjuvant. The VST-06330 EP plus BeetleGone! Bt treatment used LI-700 at 0.125% vol/vol as an adjuvant. All other treatments included Dyne-amic as an adjuvant at 0.25% vol/vol. On 14 Sep, 50 mature-green to ripe fruit were harvested from the center row of each replicate (200 per treatment) and examined for Lepidopterous internal damage TFW, external damage BAW, hemipterous pests (lygus and SB), and PW. Data were analyzed with ANOVA and Fisher’s protected LSD analysis to detect differences among treatment means (P < 0.05 level, Fisher’s protected LSD test).