Erythritol, an Artificial Sweetener, Is Acaricidal Against Pest Mites and Minimally Harmful to a Predatory Mite.

Erythritol, an artificial sweetener, has shown promise as an organic, human-safe insecticide. Recently, erythritol applications were shown to be successful at controlling pear psylla (Cacopsylla pyricola (Förster)) (Hempitera: Psyllidae), the most important pest of pear in the Pacific Northwest, USA. Twospotted spider mite (Tetranychus urticae Koch) (Trombidiformes: Tetranychidae) and pear rust mite (Epitrimerus pyri (Nalepa)) (Trombidiformes: Eriophyidae) can also be highly damaging pear pests. Their common natural enemy, Galendromus occidentalis (Nesbitt) (Mesostigmata: Phytoseiidae), can provide biological control if selective pesticides are used for managing other pests. Through a series of bioassays, we sought to determine whether erythritol could also be used for controlling either species of pest mite. We also examined whether erythritol had acute or sublethal impacts on G. occidentalis, through a variety of exposure methods. Effects examined included mortality, fecundity, prey consumption, and locomotion. We determined that a high concentration of erythritol (30%) had efficacy against both pest mite species and caused arresting behavior in twospotted spider mite. Erythritol caused little acute mortality in G. occidentalis, but did reduce fecundity and prey consumption through some exposure methods. Through motion-capture software, we determined that this is primarily due to reduced movement, likely caused by difficulty walking on residues and excessive grooming behavior. Because the predatory mite non-target effects were less acute than those for the two pest mites, we concluded that erythritol could likely be integrated into pear IPM with little or no disruption of mite biological control.

Confirmation and efficacy tests against codling moth and oriental fruit moth in peaches and nectarines using combination heat and controlled atmosphere treatments.

Two high-temperature, forced air treatments under controlled atmosphere conditions, called CATTS for controlled atmosphere/temperature treatment system, were developed for control of all life stages of codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), infesting peaches and nectarines (both Prunus spp.). These treatments were used in efficacy and confirmation tests to kill > 5,000 fourth instar oriental fruit moths and > 30,000 fourth instar codling moths with zero survivors. The treatments consist of linear heating rates of either 12 or 24 degrees C/h to a final chamber temperature under a 1% O2, 15% CO2, and > 90% RH atmosphere with air speed between 1.2 and 2.0 m/s. At a 12 degrees C linear chamber heating rate, treatment takes approximately 3 h to reach a final chamber temperature of 46 degrees C. The average lowest core temperatures of the fruit reached 43.8 degrees C within the last 30 min of the treatment. At a 24 degrees C linear chamber heating rate, it takes approximately 2.5 h to reach a final chamber temperature of 46 degrees C. The average lowest core temperatures of the fruit reached 44.6 degrees C for the last 15 min of the treatment. It also was determined that both treatments did not significantly alter the quality parameters that were evaluated to a degree that would have negatively influenced the marketability of the fruit. Positive benefits of treatment included a slower ripening of treated fruit and an inhibition of the loss of juiciness during storage in some cultivars. These treatments may be used to replacement to methyl bromide fumigation for conventional fruit or as a new treatment for organic fruit contingent upon importing country approval.

Confirmation and efficacy tests against codling moth and oriental fruit moth in apples using combination heat and controlled atmosphere treatments.

Codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), are serious pests of apples (Malus spp.) grown in the United States and other countries. In countries where these species are not found, there are strict quarantine restrictions in place to prevent their accidental introduction. The treatment used in this study consisted of hot, forced, moist air with a linear heating rate of 12 degrees C/h to a final chamber temperature of 46 degrees C under a 1% oxygen and 15% carbon dioxide environment. We found that the fourth instar of both species was the most tolerant to the treatment, with equal tolerance between the species. Efficacy tests against the fourth instar of both oriental fruit moth and codling moth by using a commercial controlled atmosphere temperature treatment system chamber resulted in > 5,000 individuals of each species being controlled using the combination treatment. Confirmation tests against codling moth resulted in mortality of > 30,000 fourth instars. These treatments may be used to meet quarantine restrictions for organic apples where fumigation with methyl bromide is not desirable.

Combined heat and controlled atmosphere quarantine treatments for control of western cherry fruit fly in sweet cherries.

Nonchemical quarantine treatments, using a combination of short duration high temperatures under low oxygen, elevated carbon dioxide atmospheric environment were developed to control western cherry fruit fly, Rhagoletis indifferens Curran, in sweet cherries, Prunus avium (L.). The two treatments developed use a chamber temperature of 45 degrees C for 45 min and a chamber temperature of 47 degreesd C for 25 min, both under a 1% oxygen, 15% carbon dioxide, -2 degrees C dew point environment. Both these treatments have been shown to provide control of all life stages of western cherry fruit fly while preserving commodity market quality. There was no definitive egg or larval stage, which was demonstrated to be the most tolerant to either controlled atmosphere temperature treatment system treatment. Efficacy tests for both treatments resulted in 100% mortality of >5000 western cherry fruit flies in each treatment. These treatments may provide, with further study, quarantine security in exported sweet cherries where western cherry fruit fly is a quarantine concern and fumigation with methyl bromide is not desired.