Towards a sustainable control of arthropod pests in Douro Demarcated Region vineyards with emphasis on the grape berry moth, Lobesia botrana (Denis & Schifermüller)
Ficheiros
Data
2017
Título da revista
ISSN da revista
Título do Volume
Editora
Resumo
The aim of the present thesis was to contribute to the development of an environmentally
sustainable pest management strategy for controlling the main arthropod pests in Douro
Demarcated Region (DDR) vineyards, with emphasis on the grape berry moth, Lobesia
botrana, a key-pest of the crop in this region. Due to the impact of L.botrana in the quality
of the wines produced in DDR, the increasing regulation of pesticides in Europe and the
increasing interest for sustainable production approaches, we intend to contribute for the
development of an effective control strategy against this pest, based on conservation
biological control and mating disruption technique with the support of degree-day models
to better timing sampling or control operations and ultimately to improve Integrated Pest
Management tactics.
With the overall goal mentioned, the following aspects were studied: a) evaluation of the
impact of non-crop habitats (NCH) adjacent to vineyards as well as ground cover
vegetation of terraced vineyards, on the overall biodiversity of arthropods, including
natural enemies (predators and parasitoids) and main vineyard pests; b) survey of L.
botrana parasitoids carried over a nine-year period; c) development of a degree-day
(DDº) models to predict the occurrence of the main phases of the flight curve of L.
botrana; two starting points for degree-day accumulation were tested, a biological event
(the first male catch) and a calendar date (January 1st) and d) evaluation of the
effectiveness of using mating disruption technique (MD) against L. botrana in DDR, as
well as identification of main constraints to its use in the region.
The results obtained showed the importance of maintaining both NCH on the
neighborhood of vineyards and vegetation of slopes and horizontal alleys to enhance
functional biodiversity of this agroecosystem. It was found that they could act as potential
ecological infrastructures in the increase of populations of natural enemies of vineyard´s
pests, namely predators (spiders and coccinelids) and parasitoids.
Although closely related groups displayed different responses to land use and habitat
preferences, the abundance of omnivores and predators was, in general, higher in NCH
than in vineyards. Preserving NCH near the vineyards, as well as promoting local
vegetation, enhances the presence of ground-dwelling arthropods.
It was found that the complex of L. botrana parasitoids, as well as the potential role played
by each species to control the pest, are greatly variable in space and time, with the rates of parasitism being substantially higher in the pest 1st generation compared to that of the
other two generations. The most promising candidate to enhance conservation biological
control of L. botrana in DDR vineyards is Elachertus sp. (Hym: Eulophidae). This is
because, on one hand, this larval ectoparasitoid has a wide geographical distribution in
the studied region and on the other hand, in most favorable conditions, the percentage of
parasitism can reach 60%, mainly in the 1st generation of the pest. Campoplex capitator
and Brachymeria tibialis appears to have a complementary role on the parasitism of the
first and second generations of L. botrana, respectively. Moreover, it was found that the
parasitism rate was related with ground cover management and chemical treatments.
Results suggest that, for enhancing conservation biological control of L. botrana in DDR,
a high abundance and diversity of vegetation (ground covers) inside or at the edge of
vineyards plots should be enhanced and a selection of pesticide with minimal risks to
parasitoid´s activity should be performed.
Nonlinear models based on Boltzmann regression equations were developed and
predicted with reasonable accuracy the flight phenology of L. botrana, although the one
that use first catches as starting point for accumulation was more accurate on predicting
the second and third flights of the insect. Even though the use of a biofix, here considered
to be a biological event, seems to improve the model accuracy, the use of a fixed calendar
date (January 1st) should be preferred, from the practical point of view and considering
large scale application of an IPM strategy.
In general MD was more effective in years of low pest population density, when applied
in large areas, with more points of release per hectare, and after consecutive seasons.
Some major constraints to the use of this technique in DDR could be identified, namely:
the high biotic potential of L. botrana; the climate conditions, particularly the high
summer temperatures; the effect of the winds on the distribution of the pheromone on the
hill; the impact of slope; the fragmentation of many vineyards and the size of the treated area.
Descrição
Tese de Doutoramento em Ciências Agronómicas e Florestais
Palavras-chave
Biodiversidade , Controle biológico de conservação , Infraestruturas ecológicas , Gestão integrada de pragas , Interrupção do acasalamento