Integrated Pest Control in Viticulture

R. Cavalloro

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000448337
• Edition: 1
• Topic: Sciences biologiques
• Subtopic: Entomologie

This book presents some conditions and/or factors which are little known as possibly affecting moth population density, or have been little-studied and, determines their possible usefulness for integrated pest control in vineyards.

Session 1
Insects and mites

Chairman: M. Tzanakakis

Little-suspected conditions possibly affecting the population size of European grape berry moths

M.E. Tzanakakis

Laboratory of Applied Zoology and Parasitology, University of Thessaloniki, Greece

Summary

Data are presented, from the literature, 1) on the occurrence of insect-pathogenic viruses and protozoa on Lobesia botrana (Denis and Schiffermueller) and Eupoecilia ambiguella (Huebner), 2) on the beneficial effect on Lobesia larvae and adults of grapes infected in the laboratory with Botrytis cinerea Pers., 3) on the occurrence of diapause in Lobesia under summerlike conditions, and 4) on the suitability of host plants other than the grapevine for larval growth. The possible effects of those conditions and/or factors and of certain cultural practices on berry moth population density are discussed within the frame of integrated pest control in vineyards.

1. Introduction

The two European grape berry moths, Lobesia botrana (Denis and Schiffermueller) and Eupoecilia ambiguella (Huebner), have long been important nests of vineyards in most European countries. Research on their biology and control has been extensive, and its results “presented in many important papers by French, German, Italian, Soviet, and Swiss scientists. In addition to supervised chemical control in which pheromone traps are used to determine when to spray, microbial control and male confusion have also been tested with encouraging results. The development of integrated pest control often requires a detailed knowledge of the pest’s biology, habits and ecological associations. Factors causing relatively low mortality may contribute considerably to the success of integrated control, if a single method is not sufficient. The purpose of this paper is to present some conditions and/or factors which I feel are little known as possibly affecting moth population density, or have been little-studied and, therefore, require further study to determine their possible usefulness for integrated pest control in vineyards.

2.1. Insect pathogens

P. Marchal already in 1911 reported an infection of Lobesia larvae by a sporozoan and Paillot in 1941 described a microsporidian from infected larvae of Eupoecilia (8). Lipa (8) found it in Lobesia larvae, pupae and adults in laboratory cultures and in the field, in France and Czechoslovakia. It is transmitted transovarially and through spermatophores, thus being easily spread. Lipa (8) suggests that the high incidence of infection in a field population he sampled indicates that this pathogen may be a useful agent of biological control of Lobesia.

The fact that no virous diseases of berry moths were known twenty (2) or even ten years ago, may be the reason why research in this field has long been neglected. In 1979, Deseő et al. (3) reported on the occurrence of virous diseases of Lobesia in Italy, and two years later (4) gave further details. Those scientists of the University of Bologna, checking older and recent literature, concluded that discrepancies in the literature suggest that “factors other than pure ecological preference or ecological plasticity of Lobesia adults might play a role in its population dynamics”. They subsequently looked into the reasons for abrupt changes in population density this insect from year to year in central-northern Italy. Eggs they collected gave larvae that died in the first two instars. Their work yielded three pathogens in Lobesia larvae and adults: a cytoplasmic polyhedrosis virus (CPV), a species of Protozoa, Microsporida, and another virus, probably a baculovirus, The first two pathogens are known to cause chronic diseases in insects. In one vineyard, the moth’s copulation collapsed in 3 years. The epidemics were considered to be the result of the joint action of the CPV and the protozoan. Without questioning the important role of climatic factors, Deseő et al. (4) showed that pathogens had a decicive influence on the population dynamics of Lobesia. This could explain the different population flunctuations between different vineyards and grapevine cultivars which are within the same region and have similar weather and topographic conditions. The disease is certainly worth taking advantage of, especially where ambient temperatures are favorable for the expression of the symptoms of the disease. Even where relatively high temperatures do not allow the expression of the disease symptoms, the infected insects may be more susceptible to other mortality factors.

Two years ago, specimens of a Lobesia colony of our laboratory, which had been maintained for years on an artificial larval diet and originated from northern Greece, was found by Deseő and collaborators to be infected by at least two pathogens: a protozoan of the Microsporida, and a virus. Only a small percentage of the eggs laid by moths of that diseased stock gave viable larvae (K.V. Deseő, in litteris). Therefore, there should be little doubt about viruses and protozoa occurring on Lobesia also in other European countries. The fact that some of them cause debilitating diseases and some do not cause symptoms under relatively high temperatures, thus escaping notice, calls for detailed surveys and...