Assessment of feasibility for guava (Psidium guajava) grown in the fixed structure of field net-house

The feasibility of growing 5-year-old “Jen-Ju Ba” guava (Psidium guajava) plants in a fixed field net-house to reduce the amount of shoot and fruit damage caused by typhoons was evaluated in Taiwan in 2013. The field net-house was 2.6-m high and covered with 16-meshes white-net. The plants grown in the field served as the control. Because no typhoon struck Taiwan during the experimental period, only the climate, yield tree^-1, fruit quality, percentage of matured fruit, and types of pest could be compared. The temperature and humidity were not significantly different between the field net-house and the field, but the 16-mesh net-house shielded 21, 12.5, and 2.5% of the photosynthetic photon flux density (PPFD) relative to the control in summer, autumn, and winter, respectively. The main pests were guava leaf and shoot webber (Spilonota rhothia) and thrips (Rhipiphorothrips cruentatus) in the field and guava mealybug (Planococcus minor) and cotton aphid (Aphis gossypii) in the net-house. However, fruit rot disease was mainly caused by guava scab (Pestalotiopsis psidii) and black spot (Guignardia psidii) in both treatments. The annual yield tree^-1 was higher in the field than in the net-house (87.1 vs. 73.6 kg, respectively) as was the total soluble solids content of fruit in winter, possibly because of the additional shading. However, no other fruit characteristics differed between the two treatments.