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.
The potato/tomato psyllid,Bactericera cockerelli(Sulc) (Hemiptera: Triozidae) has been a major pest of solanaceous crops for decades. This pest can cause damage to crop plants by direct feeding and, as has been recently discovered, by transmitting the bacterial pathogenCandidatusLiberibacter psyllaurous (a.k.a.Ca.L. solanacearum). Many studies have been conducted to determine the relationship of this pest to plant injury and to develop management strategies to alleviate the damage caused by this pest in a wide variety of solanaceous plants. Studies in the past decade have documented substantial genetic variability in this invasive species, enhanced our rapidly-evolving understanding of the interactions between the insect and the pathogen it carries, and improved our appreciation of the invasive potential of the pest. This review seeks to provide a comprehensive update toB. cockerellilife history, relationship to plant diseases, and the current state of management strategies againstB. cockerelli.
Honey bees (Apis mellifera L.) are important ecological and agricultural resources. They are among the most widely available pollinators and provide products as well as services. Unfortunately, honey bee populations are susceptible to several environmental threats, including heavy metal exposure. Honey bees can be exposed to heavy metals when foraging on contaminated honey and pollen resources, and in some cases by airborne exposure. We studied the joint acute and chronic effects of cadmium (Cd) and copper (Cu) on A. mellifera. A 1:1 solution of the two heavy metals increased larval developmental duration and the mortality of both larvae and foragers in a dose-dependent way, decreased forager feeding, increased body metal burdens, and disrupted the sucrose response behavior of foragers. In combination, Cd and Cu demonstrated a weakly synergistic effect on foragers, but for larvae an initially antagonistic effect at low doses changed to strongly synergistic response at higher concentrations. The sucrose response threshold of foragers decreased significantly when they were dosed with increasing concentrations of the metal mixtures. Overall, the fitness of honey bee larvae and foragers is detrimentally affected when these metals co-occur.