The Hualien District Agricultural Research and Extension Station has introduced a sun-protection growing bag specifically for red-flesh guavas, aiming to address challenges posed by rising temperatures and intense sunlight in Taiwan's Yilan Plain. This region is known for its red-flesh guava variety, which is particularly vulnerable to sunburn during its ripening period from June to August.
Red-flesh guavas, unlike the more common white-flesh "pearl" guavas, are susceptible to sun damage when exposed to temperatures of 35°C or higher for over two-and-a-half hours. Traditional plastic growing bags exacerbate the issue by raising internal temperatures to over 45°C, potentially leading to severe sunburn and reduced market value.
To combat these conditions, the station developed a growing bag utilizing a patented polyethylene material on one side, capable of reducing internal temperatures by up to 13.8°C at midday during summer. The opposite side features transparent plastic for monitoring fruit maturity. Tests indicated a 70% reduction in sunburn incidence, a 13.6% increase in average fruit weight, and a 1.3° Brix enhancement in sweetness.
Despite the advanced bag's cost of NT$8 to NT$8.5 (US$0.25 to US$0.27), it is needed for only 15 to 20 percent of guavas exposed to direct sunlight. Trials across seven guava farms in Yilan County demonstrated potential profit increases of about NT$12,000 (approximately US$375) per square meter. This technology may extend its benefits to other guava varieties.
Source: Taipei Times