Nitric Oxide Fumigation for Control of Bulb Mites on Flower Bulbs

Nitric Oxide Fumigation for Control of Ham Mite, Tyrophagus putrescentiae (Sarcoptiformes: Acaridae)

The ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), is a common pest infesting several stored products, particularly the aged hams. In this study, we reported the efficacy of nitric oxide (NO) fumigation, a recently discovered fumigation treatment under the ultra-low oxygen environment, at various concentrations and time under the laboratory conditions at 25°C against different mite stages on both dietary media and ham meat. Our results showed that NO fumigation was effective against all mite stages and 100% control was achieved. Generally, the egg was the most tolerant stage and required 48-, 24-, 16-, and 8-h treatments to achieve 100% mortality at 0.5, 1, 1.5, and 2% NO concentration on dietary media, respectively. Tyrophagus putrescentiae mobile immatures and adult stages were less tolerant, and 100% mortality was achieved after 16-, 8-, 8-, and 4-h treatment at 0.5, 1, 1.5, and 2% NO, respectively. The median lethal concentration (LC50) of NO on egg was 0.86, 0.68, and 0.32% for 8-, 16-, and 24-h treatments. In addition, a confirmatory test was conducted on ham meat at 0.5 and 1.0% of NO and similar efficacy was found. Complete control of egg was achieved after 48- and 24-h treatment at 0.5 and 1.0% of NO, respectively, and larvae and adult mites were 100% controlled after 16 and 8 h at 0.5 and 1.0% of NO, respectively. Our results demonstrated that NO fumigation was effective against T. putrescentiae and can be a potential alternative treatment to methyl bromide for cured-ham pest control.

Nitric oxide fumigation for postharvest pest control on lettuce

BACKGROUND

The lettuce aphid, Nasonovia ribisnigri, and western flower thrips, Frankliniella occidentalis, are quarantine pests of lettuce in Asian markets and, therefore, require treatments on lettuce exported from USA to Japan and Taiwan, respectively. Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control and has been demonstrated as safe to fresh fruit and vegetables. In this study, small-scale NO fumigations were conducted to determine effective treatments and large-scale confirmatory tests were conducted to determine the efficacy against N. ribisnigri and F. occidentalis on commercially packed lettuce. The safety of NO fumigation to postharvest quality of lettuce was also evaluated.

RESULTS

In small-scale experiments, complete control of N. ribisnigri was achieved in 3, 8, and 16 h fumigations with 2.0%, 1.0%, and 0.5% NO, respectively, at 2 °C on both iceberg and romaine lettuce. In a large-scale experiment, complete control of both N. ribisnigri and F. occidentalis was achieved in a 16 h fumigation with 0.5% NO at 2 °C. The fumigation treatment had no effect on either external or internal postharvest quality of lettuce at 14 days after treatment.

CONCLUSION

Nitric oxide fumigation was demonstrated to be effective against both N. ribisnigri and F. occidentalis and safe to lettuce quality in large-scale fumigations of commercially packed lettuce. The study suggests that NO fumigation has the potential to be an alternative treatment to methyl bromide for postharvest pest control on harvested lettuce. © 2018 Society of Chemical Industry.

Nitric Oxide Fumigation for Control of Spotted Wing Drosophila (Diptera: Drosophilidae) in Strawberries

Nitric oxide (NO) fumigation was conducted to determine the efficacy of controlling spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), in strawberries and the effects on postharvest quality of strawberries under ultralow oxygen conditions at 2°C. Eight-hour fumigations with 1.0 and 3.0% NO were tested against different life stages of the insect to determine an effective treatment, and a 16-h fumigation was tested to determine the impact on strawberry quality. Complete control of eggs and larvae in strawberries was achieved in an 8-h fumigation with 3.0% NO, and the treatment achieved 98.8% mortality of pupae. The first and second instars were more susceptible to NO and were completely controlled with 1.0% NO fumigation. The 16-h fumigation treatment with 3.0% NO had no negative impact on strawberry quality as there were no significant differences from the control in berry damage score. The NO fumigation, however, significantly reduced mold 2 wk after fumigation, indicating that NO fumigation had potential to preserve strawberry quality. The results of this study demonstrated that NO fumigation is effective for control of SWD and safe to strawberries, and therefore, NO fumigation has potential to control SWD on harvested strawberries.