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Effects of grapevine bunch exposure to sunlight on berry surface temperature and Lobesia botrana ( L epidoptera: T ortricidae) egg laying, hatching and larval settlement
Author(s) -
Kiaeian Moosavi Fatemeh,
Cargnus Elena,
Pavan Francesco,
Zandigiacomo Pietro
Publication year - 2018
Publication title -
agricultural and forest entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.755
H-Index - 55
eISSN - 1461-9563
pISSN - 1461-9555
DOI - 10.1111/afe.12274
Subject(s) - tortricidae , biology , lepidoptera genitalia , berry , horticulture , hatching , larva , infestation , sunlight , botany , zoology , physics , astronomy
Bunch‐zone leaf removal reduced infestation by Lobesia botrana , although the mechanism responsible for this effect is unknown. Based on the mortality of eggs and newly‐hatched larvae exposed to high temperatures (≥37 °C) in the laboratory, the present study aimed to assess the influence of (i) bunch‐zone leaf removal and grapevine‐row orientation on berry surface temperature and (ii) bunch exposure to sunlight on egg and larval mortality. Berry temperatures were measured using a noncontact infrared thermometer in two vineyards and showed that, in direct sunlight, the temperatures of berry surfaces were 9 °C or more above air temperature, and the highest mean temperatures occurred on southwest‐side bunches followed by west‐ and south‐side bunches. The results of four two‐choice field assays, carried out confining fertile females in cages with two bunches, one exposed and one non‐exposed to sunlight, showed that: (i) the females did not avoid laying eggs on sun‐exposed bunches and (ii) the lowest percentages of both egg‐hatching and larval settlement occurred on sun‐exposed bunches. The hypothesis that the high temperatures reached by sun‐exposed berries cause egg and especially larval mortality is confirmed. Bunch‐zone leaf removal combined with optimized grapevine‐row orientations can improve L. botrana control.