Kiwifruit under plastic covering: impact on fruit quality and on orchard microclimate

Abstract

Italy has a preeminent rank in kiwifruit industry, being the first exporter and the second largest producer after China. However, in the last few years kiwifruit yields and the total cultivated area considerably decreased, due to the disease spread of the bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). Bacterial canker has affected significantly orchards productivity and consequently has caused severe economic losses in all major areas of kiwifruit cultivation, including Italy,and considerable damage to the international kiwifruit industry.Several climatic conditions and cultural practices affect the development of the bacterial canker.Orchard hygiene, restrictions on the movement of nursery plants, orchard management and cultural practices, chemical and biological controls and breeding programs are being employed to limit the diffusion of the disease and help kiwifruit orchards to survive and produce. A possible way seems to be the modification of environmental conditions and it is being explored through the building of plastic covers over the orchards. This research work is focused on the impact of plastic cover on fruit quality, microclimate conditions and incidence of Psa. To evaluate the impact of plastic cover on microclimate, quality of fruits and disease incidence the following parameters were evaluated: climatic parameters (temperature, PAR), quality parameters (color, fruit firmness, titratable acidity, °Brix, vitamin C), disease incidence (%). The use of a permanenttunnel modify light intensity and microclimate without any negative consequences on kiwifruits quality. Covering a kiwifruit orchard with a protective canopy reduces the spread of Psa throughout the orchard when covers are constructed over vines with low levels of infection.The use of plastic covers ensure the production of the current and future kiwifruit without compromising the quality of the fruit, but future trials will provide further information clarifying the effectiveness of the actual crop covers.

Mitigation of Emergent Bacterial Pathogens Using Pseudomonas syringae pv. actinidiae as a Case Study—From Orchard to Gene and Everything in Between

“…To decrease the influence of environmental conditions that favor pathogen growth, several solutions have been suggested during the last decade, such as the use of fans, under-vine shelters, and overhead irrigation [61,118,119]. Protection against rain, wind, and hail can be provided by the installation of windbreaks (either artificial or natural) and coverings (made of plastic or cloth) to diminish bacterial spread and the incidence of plant wounding [118][119][120]. However, these structures pose added costs to orchard management, and very little is known about how they may affect plant productivity.…”

Effect of Photo-Selective Nets on Yield, Fruit Quality and Psa Disease Progression in a ‘Hayward’ Kiwifruit Orchard

“…Warmer temperatures, particularly the mean maximum air temperature, together with lower RH and the reduction in rainfall under the nets, can explain the trend of decreased severity of Psa disease symptoms under the photo-selective nets, because these climatic conditions limit the bacteria's development [35]. Air temperatures over 20 • C seem to decrease Psa disease symptoms, as well as the dryer leaves limiting pathogen spread within the canopy [16,18,19]. Moreover, other benefits of the nets include protection from wind and hail that can result in physical damage to the vines, predisposing them to infection [18].…”

“…actinidiae (Psa) is responsible for high yield losses worldwide [15,16], and environmental stresses such as frost, wind, rain and hail storms are favourable for the spread and development of this disease [15,17]. Plastic covers, as well as photo-selective nets, have emerged as a promising strategy to manage control of Psa [18,19].…”

Chlorophyll measurements in Alstroemeria sp. using SPAD-502 meterand the color space CIE L*a*b*, and its validation in foliar senescence

“…The color spaces (L*, a*, b*), measured by CIE L*a*b* have been used to evaluate the color of some horticultural products (flowers, fruits, vegetables) (Chiabrando and Giacalone 2018, Teppabut et al 2018, Gracia-Romero et al 2019. Some studies indicated that the color space CIE L*a*b* can be used to study senescence (Teppabut et al 2018, Luo et al 2020 only when the factors that influence the color perception (light intensity, saturation, and angle) are controlled and homogenized (McGuire 1992, Gevers and Smeulders 1999, Gómez-Polo et al 2016.…”