Chapter I. In the context of IPM strategies, this PhD thesis aims to investigate the possibility to control grapevine pests through environmental-friendly strategies, such as cultural practices and conservation biological control. Moreover, since cultural practices can also influence the spreading of bunch rots due to Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), the relation between the moth and Botrytis cinerea Pers. Fr. was also examined. Chapter II. Bunch-zone leaf removal (BLR) in vineyards was reported as an effective cultural practice to prevent botrytis or L. botrana attacks. Field trials were carried out to study the effects of BLR on the two carpophagous generations of the moth and grey mould, simultaneously. BLR applied at the pea-sized berry stage or some days later, during the moths’ second-flight, reduced infestation of both carpophagous generations of L. botrana and botrytis infection at harvest time. Investigating the effects of BLR on spatial distribution of L. botrana larval nests within canopy and eggs on bunches, in relation to sunlight exposure, a lower larval infestation on bunches exposed to sunlight by BLR and more eggs laid on berries exposed to sun than on those facing towards the interior part of the canopy were observed. The female non-avoidance of laying eggs on the sun-exposed side of bunches supports the hypothesis that BLR affects L. botrana larval infestation by increasing egg/larval mortality. Chapter III. Based on high temperatures of berries recorded in vineyards, eggs and larvae of L. botrana were exposed to high temperatures in the laboratory. In the field trials effect of different grapevine row-orientation on berry temperature was studied as well as the influence of berry exposure to sunlight on egg distribution, mortality and larval settlement. In the laboratory egg and larval mortality occurred from 40 °C and 37 °C respectively. The berries exposed to sunlight can exceed the air temperature of more than 10 °C, so air temperature higher than 30 °C can determine the berry temperatures the same as those associated with egg/larval mortality in the laboratory. Both the field and laboratory data showed a higher larval-susceptibility to high temperatures comparing to eggs. Therefore, the cultural practice of BLR reduces L. botrana infestation because exposure to sunlight determines high berry temperatures and subsequently egg/larval mortality. Chapter IV. Based on the frequent coincidence of L. botrana and botrytis attacks in vineyards and on the fact that fungus in some experiments favoured female egg-laying, and improved larval performance and female fecundity, some research suggest a mutualistic relationship between the moth and the fungus, and suppose a positive role of fungal sterols in L. botrana performance. On the other hand the data reported in literatures about the effect of botrytis on L. botrana are not always in agreement with each other. Since some of previous research showed a positive effect of botrytis on L. botrana performance adding it to an artificial diet (diet B) with a lower sterol richness than berries, the first step of this research was to compare the performance of larvae fed on three basic diets [i.e., berries (250 mg/100 g sterol content), artificial diets A (160 mg/100 g sterol content) and B (80 mg/100 g sterol content)]. The results showed higher mortality, longer development duration and lower mandible size for larvae fed on diet B in comparison with those on berry diet and diet A. For the second step, dried powder of botrytis was prepared in the laboratory and added to the two artificial diets. Thus, five treatments, i.e. diets A and B with or without botrytis addition, and berries were compared. The addition of botrytis was effective in improving larval performance only for diet B, that is poorer in sterol than both diet A and berry diet. To study the oviposition preference of L. botrana female toward botrytis-infected bunches in the field, mated females were released in cages with one healthy and one infected bunch and the number of laid eggs was counted in the laboratory. No preference of females was observed toward infected bunches and infected berries in the field. These data showed that previous research did not definitively prove that botrytis promotes larval performance and females are not stimulated to lay more eggs on botrytis-infected bunches in the field. Chapter V. In the context of conservation biological control, the influence of two different inter-row management, i.e. tillage (bare soil between rows by cultivation) and mowing (presence of green cover), and two clones of grapevine cv Sauvignon (R3 and R297) on the population of grapevine arthropod pests and their natural enemies were studied in an organic vineyard. Samplings were carried out over two years in the vineyard through grapevine leaf and bunch observations in the field and in the laboratory, beating tray and yellow sticky traps. Most important sap-sucker grapevine pests (i.e., leafhoppers and thrips) and natural enemies, both specialist and generalist, such as Araneae (spiders), Coleoptera Coccinellidae, Dermaptera, Heteroptera Nabidae, Thysanoptera Aeolothripidae and Acari Phytoseiidae were monitored. Pruning weight and Normalized Difference Vegetation Index were also considered to estimate grapevine vigour. The mowing of inter-rows (vs. tillage) reduced the leafhopper populations (i.e., Empoasca vitis and Zygina rhamni), as a consequence of the lower plant vigour, and the vine thrips Drepanothrips reuteri populations, due to the greater occurrence of their Aeolothrips sp. predators. The green cover did not affect L. botrana infestation, but the amount of rotten berries contiguous to larval nests may have been reduced since it decreased the botrytis incidence. A role of spiders in pest control could be also supposed, because their population density was favoured by the green covered inter-rows.

Studies on environmental-friendly strategies for the management of Lobesia botrana (Lepidoptera: Tortricidae) and other grapevine pests / Seyedehfatemeh Kiaeianmoosavi - Udine. , 2016 Apr 07. 28. ciclo

Studies on environmental-friendly strategies for the management of Lobesia botrana (Lepidoptera: Tortricidae) and other grapevine pests

KIAEIANMOOSAVI, SEYEDEHFATEMEH
2016-04-07

Abstract

Chapter I. In the context of IPM strategies, this PhD thesis aims to investigate the possibility to control grapevine pests through environmental-friendly strategies, such as cultural practices and conservation biological control. Moreover, since cultural practices can also influence the spreading of bunch rots due to Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), the relation between the moth and Botrytis cinerea Pers. Fr. was also examined. Chapter II. Bunch-zone leaf removal (BLR) in vineyards was reported as an effective cultural practice to prevent botrytis or L. botrana attacks. Field trials were carried out to study the effects of BLR on the two carpophagous generations of the moth and grey mould, simultaneously. BLR applied at the pea-sized berry stage or some days later, during the moths’ second-flight, reduced infestation of both carpophagous generations of L. botrana and botrytis infection at harvest time. Investigating the effects of BLR on spatial distribution of L. botrana larval nests within canopy and eggs on bunches, in relation to sunlight exposure, a lower larval infestation on bunches exposed to sunlight by BLR and more eggs laid on berries exposed to sun than on those facing towards the interior part of the canopy were observed. The female non-avoidance of laying eggs on the sun-exposed side of bunches supports the hypothesis that BLR affects L. botrana larval infestation by increasing egg/larval mortality. Chapter III. Based on high temperatures of berries recorded in vineyards, eggs and larvae of L. botrana were exposed to high temperatures in the laboratory. In the field trials effect of different grapevine row-orientation on berry temperature was studied as well as the influence of berry exposure to sunlight on egg distribution, mortality and larval settlement. In the laboratory egg and larval mortality occurred from 40 °C and 37 °C respectively. The berries exposed to sunlight can exceed the air temperature of more than 10 °C, so air temperature higher than 30 °C can determine the berry temperatures the same as those associated with egg/larval mortality in the laboratory. Both the field and laboratory data showed a higher larval-susceptibility to high temperatures comparing to eggs. Therefore, the cultural practice of BLR reduces L. botrana infestation because exposure to sunlight determines high berry temperatures and subsequently egg/larval mortality. Chapter IV. Based on the frequent coincidence of L. botrana and botrytis attacks in vineyards and on the fact that fungus in some experiments favoured female egg-laying, and improved larval performance and female fecundity, some research suggest a mutualistic relationship between the moth and the fungus, and suppose a positive role of fungal sterols in L. botrana performance. On the other hand the data reported in literatures about the effect of botrytis on L. botrana are not always in agreement with each other. Since some of previous research showed a positive effect of botrytis on L. botrana performance adding it to an artificial diet (diet B) with a lower sterol richness than berries, the first step of this research was to compare the performance of larvae fed on three basic diets [i.e., berries (250 mg/100 g sterol content), artificial diets A (160 mg/100 g sterol content) and B (80 mg/100 g sterol content)]. The results showed higher mortality, longer development duration and lower mandible size for larvae fed on diet B in comparison with those on berry diet and diet A. For the second step, dried powder of botrytis was prepared in the laboratory and added to the two artificial diets. Thus, five treatments, i.e. diets A and B with or without botrytis addition, and berries were compared. The addition of botrytis was effective in improving larval performance only for diet B, that is poorer in sterol than both diet A and berry diet. To study the oviposition preference of L. botrana female toward botrytis-infected bunches in the field, mated females were released in cages with one healthy and one infected bunch and the number of laid eggs was counted in the laboratory. No preference of females was observed toward infected bunches and infected berries in the field. These data showed that previous research did not definitively prove that botrytis promotes larval performance and females are not stimulated to lay more eggs on botrytis-infected bunches in the field. Chapter V. In the context of conservation biological control, the influence of two different inter-row management, i.e. tillage (bare soil between rows by cultivation) and mowing (presence of green cover), and two clones of grapevine cv Sauvignon (R3 and R297) on the population of grapevine arthropod pests and their natural enemies were studied in an organic vineyard. Samplings were carried out over two years in the vineyard through grapevine leaf and bunch observations in the field and in the laboratory, beating tray and yellow sticky traps. Most important sap-sucker grapevine pests (i.e., leafhoppers and thrips) and natural enemies, both specialist and generalist, such as Araneae (spiders), Coleoptera Coccinellidae, Dermaptera, Heteroptera Nabidae, Thysanoptera Aeolothripidae and Acari Phytoseiidae were monitored. Pruning weight and Normalized Difference Vegetation Index were also considered to estimate grapevine vigour. The mowing of inter-rows (vs. tillage) reduced the leafhopper populations (i.e., Empoasca vitis and Zygina rhamni), as a consequence of the lower plant vigour, and the vine thrips Drepanothrips reuteri populations, due to the greater occurrence of their Aeolothrips sp. predators. The green cover did not affect L. botrana infestation, but the amount of rotten berries contiguous to larval nests may have been reduced since it decreased the botrytis incidence. A role of spiders in pest control could be also supposed, because their population density was favoured by the green covered inter-rows.
7-apr-2016
IPM; Lobesia botrana; Grapevine pests; Grey mould; Conservation biological control; Cultural control
Studies on environmental-friendly strategies for the management of Lobesia botrana (Lepidoptera: Tortricidae) and other grapevine pests / Seyedehfatemeh Kiaeianmoosavi - Udine. , 2016 Apr 07. 28. ciclo
File in questo prodotto:
File Dimensione Formato  
10990_694_Kiaeianmoosavi thesis.pdf

Open Access dal 08/10/2017

Tipologia: Tesi di dottorato
Licenza: Non specificato
Dimensione 8.75 MB
Formato Adobe PDF
8.75 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/1132897
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact