Net Enclosure of ‘Honeycrisp’ and ‘Gala’ Apple Trees at Different Bloom Stages Affects Fruit Set and Alters Seed Production

Abstract

Thinning is a critical but challenging practice in apple production, especially for organic producers. The objective of this experiment was to determine if exclusion netting, used to manage insect pests and stress, could reduce fruit set and thinning requirements of ‘Gala’ and ‘Honeycrisp’ apple trees in Michigan and Washington, U.S.A., respectively. Nets were closed around whole canopies at different timings based on a predetermined percentage of open flowers. In 2017 and 2018, netted trees set a full commercial crop regardless of percentage of open bloom at the time of netting, including prebloom enclosures. Fruit set and yield of netted ‘Honeycrisp’ trees were significantly lower than non-netted, nonthinned controls but similar to non-netted hand-thinned controls. ‘Gala’ fruit set and yield did not differ among treatments. Exclusion netting markedly reduced the number of mature seeds and increased the number of nonfertilized seeds in both cultivars. Pollinator exclusion to ‘Gala’ in a frost year increased parthenocarpic fruit set two-fold compared to non-netted trees. Fruit size, shape, and quality attributes of ‘Gala’ were were similar among treatments, but ‘Honeycrisp’ fruit were significantly smaller than hand-thinned, non-netted controls. Netting may constitute an alternative, viable strategy to manage fruit set but requires testing on different cultivars.

Photoselective Protective Netting Improves “Honeycrisp” Fruit Quality

“…As production continues to expand, particularly in warmer regions like Washington State, the use of protective netting to minimize losses to sunburn [2] will be necessary for the economic sustainability of this cultivar. Despite numerous studies carried out on other apple cultivars like "Fuji", "Braeburn", "Jonagold", "Elstar" and "Gala" grown under shading nets [16,25,33,[47][48][49][50], there is still limited literature available about the effects of netting on "Honeycrisp" physiology, fruit quality and storability [2,4,11,51,52]. This study's objectives were to (1) characterize the light intensity and light quality under colored nets in a "Honeycrisp" orchard compared to an uncovered control and (2) investigate the effect of colored nets on external and internal fruit quality for "Honeycrisp".…”

Towards Integrated Pest and Pollinator Management in Intensive Pear Cultivation: A Case Study from Belgium

“…For instance, flower borders and/or hedgerows in field margins supplying pollen and nectar for natural enemies are often also valuable for pollinating insects and hence pollination services [10,23,24], although this is not always the case [23]. On the other hand, the expanding use of physical control measures, for example netting to exclude pest insects, can have a serious negative impact on pollinating insects [25,26]. In order to facilitate synergies between pest control practices and pollination services, the concept of IPPM was introduced and a systematic framework for this concept was recently proposed [9,11,22].…”

Influence of seed set on apple symmetry assessed by image analysis: an overlooked effect of pollination on fruit shape.

“…Despite this complexity, several studies pointed out a positive effect of pollination on apple weight (Buccheri and Vaio, 2006;Webber et al, 2020) and on apple appearance (Buccheri and Vaio, 2006;Garratt et al, 2014). The majority of the studies focusing on the pollination effect on apple appearance have explored the differences between deformed and regular fruits (Buccheri and Vaio, 2006;Elsysy et al, 2019;Herrmann et al, 2019;Matsumoto et al, 2012;Wu et al, 2021), whereas quantitative measures to assess the regularity of fruit shapes have been rarely adopted (Carisio et al, 2020;Sheffield, 2014). In these last cases, fruit shape measurements were oversimplified (e.g.…”