Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Response of 'Royal Gala' and 'Granny Smith' apples to high-temperature controlled atmosphere treatments for control of Epiphyas postvittana and Nysius huttoni.

Abstract

Controlled atmosphere (CA) establishment commenced immediately after Royal Gala and Granny Smith apples were placed in chambers. Target CA conditions (1.2% O2, 1% CO2) were attained within 6 h while the temperature was held constant at 20°C. The temperature was then increased over 8 h to achieve a temperature of 40° at the fruit surface. The treatment time was measured from the start of CA establishment. Mean LT99 values for fifth instar E. postvittana and adult N. huttoni inoculated onto apples and exposed to CA at 40° were 14.2 ± 0.1 h and 16.6 ± 0.1 h, respectively. Using the same treatment establishment protocol, apples were subjected to 40° in air or CA for 17 and 20 h. Following treatment, fruits were either hydrocooled in ambient water, or not hydrocooled, and then stored at 0° in air for 8 weeks before being transferred to 20° for 7 days and assessed for quality. With Royal Gala apples, the only treatment that showed significant damage (slight internal browning in some fruits) was the hydrocooled 17-h CA treatment. With Granny Smith, no significant damage was observed in the 40°-air treatments. Both hydrocooled and non-hydrocooled 17- and 20-h CA treatments showed significantly higher levels of damage in the form of internal browning. Granny Smith fruits treated at 40° in air or CA were more yellow than control fruits. High-temperature CA-treated Royal Gala and Granny Smith fruits were firmer than non-treated control fruits.