Impact of Exclusion Netting Row Covers on 'Honeycrisp' Apple Trees Grown under Northeastern North American Conditions: Effects on Photosynthesis and Fruit Quality.

Gérald Chouinard,Jonathan Veilleux,Mikael Larose,Vincent Philion,Daniel Cormier,Francine Pelletier,Valentin Joubert

doi:10.3390/insects10070214

Gérald Chouinard, Jonathan Veilleux + Show 5 more

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https://doi.org/10.3390/insects10070214

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Abstract

Exclusion nets have been used successfully to protect fruit from insect pests of apples under various conditions, but the effect of each particular netting system on the plant itself has rarely been investigated. In this study, a complete exclusion system—in which the soil is also excluded—was used to grow ‘Honeycrisp’ apples for six years in southern Quebec, Canada. Abiotic conditions, as well as plant photosynthesis and fruit quality characteristics (colour, firmness, size, sugar content, number of seeds, ripeness and skin integrity) and yield were estimated yearly and compared in netted (either with or without a rainproof top) and unnetted row units. Although annual variations were high and results showed little or no difference between netted and unnetted rows for all measured variables, with the following exceptions; colour (increased red surface on fruits from unnetted rows some years), size (fruits from unnetted rows were smaller) and maturity (fruits from unnetted rows matured slightly faster). Fruits produced under nets had fewer microcracks at the surface than fruits produced without nets. Reduced cracking possibly helped decrease sooty blotch and flyspeck incidence and severity. Impacts for pest control and prospects for pesticide-free production are discussed.

Highlights

Nets are commonly used as an antihail device in tree fruit production [1,2]
Exclusion systems for pests of pome and stone fruits can be grouped into two categories, depending on whether the soil is excluded from the zone or not [1,2]
This paper presents the follow-up on a previous study which focused on the plant protection properties of a row-by-row exclusion netting system [1] for ‘Honeycrisp’ apples grown in northeastern

Summary

Introduction

Nets are commonly used as an antihail device in tree fruit production [1,2]. Nets are increasingly being considered for use as a nonaggressive pest control tool—being called exclusion nets in this context [4]. The sole review [5] of the effects of agricultural nets on apple tree physiology and fruit quality focused on antihail and shading nets. Insect exclusion nets, which typically do not provide more than 10% shading, have been much less studied. Exclusion systems for pests of pome and stone fruits can be grouped into two categories, depending on whether the soil is excluded from the zone (complete exclusion) or not (incomplete exclusion) [1,2]. While incomplete exclusion can provide adequate pest control in many contexts, complete row-by-row exclusion currently appears more suited for the North

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