Parasitic weeds working group

Background

Parasitic plants are becoming a severe constraint to Mediterranean and Tropical agriculture on major crops and the efficacy of available means to control them is minimal. The most economically damaging parasitic weeds are members of the genera Striga (witchweeds) and Orobanche (broomrapes). Various species of the latter are important in southern and eastern Europe, the Middle East and North Africa. For example, O. crenata causes huge damage to legume crops (faba bean, lentil, pea and common vetch) in southern Europe; O. cumana threatens sunflower in southern and eastern Europe; O. minor is important in central Europe on clover; O. ramosa attacks potato, tobacco, tomato and hemp; and species such as O. foetida that cause problems in other parts of the world are also present in Europe.

The main focus of research on parasitic weeds has been on their management when infecting important crops. Control strategies have centred around agronomic practices and the use of herbicides, although success has been marginal. Novel integrated control programmes are necessary. In addition, global environment change together with changing land use patterns means that some geographical areas and farming systems that do not currently suffer from parasitic weeds in Europe could become affected within coming decades. It is therefore important to pre-empt the spread of parasitic weeds and to consider, for example, how quarantine regulations might achieve this.

WG Objectives

The main objective of the WG is to increase the understanding of the interaction between parasitic weeds and their hosts and to implement sustainable means to control the parasites. The lack of interdisciplinary involvement has been a major factor that has impeded progress in the sustainable control of parasitic weeds. The establishment of the new WG aims to address this deficiency, by including weed scientists who specialize in botany, ecology, plant anatomy, physiology, biochemistry, molecular biology, breeding, plant pathology, chemistry and agronomy.

Joint research within the proposed WG will encourage the transfer of fundamental research into control strategies in the field application and shall ultimately yield sustainable management measures for the variety of parasitic weeds that affect agriculture and forestry in Europe.

The WG will integrate fundamental, biotechnological and marker-technological science and applied research concepts to develop sustainable means of parasitic weed management, integrating cultural practices, genetic resistance, and novel methods of biological- and chemical control.

Research topics to be covered

Considering the involvement of groups with different expertise in the WG, many different fields of research will be covered:
Parasitic weeds of three different groups: root parasites (mainly Orobanche), climbers (Cuscuta), and mistletoes (mainly Viscum).
Physiology of parasitism: seed germination, attachment, parasite development, interactions between the host and the parasite.
Integrated weed management strategies and the economics of controlling parasitic plants.
Identification, augmentation, exploitation and formulation of biocontrol agents.
Novel cultural practices.
Molecular and classical taxonomy and race identification.
Developmental aspects of host-parasite interaction, including structural, physiological, genetic and molecular agro-ecology of parasitic plants that will have significant implications in the development of control measures.
Distribution, incidence and importance of the parasitic weeds in Europe, including the invasion and progression of parasitic weeds under predicted global climate change scenarios, as well as evolutionary changes within the species.
Quarantine measures and regulations for control of spread of parasitic plants.
Monitoring the parasitic plant populations for frequency of virulence factors and for genetic variation.
Development and evaluation of methods for screening and assessment of crop resistance to parasitic plants, and identification of both resistance genes and resistance mechanisms.

Potential interactions with already existing EWRS Working Groups

Many interactions with the other EWRS WGs are possible, thus the proposed WG is anticipated to be highly interactive. For example, we will have collaboration with:

WG "Crop/Weed Interactions", because parasitic plants have a very strict contact with and dependence on crop plants;
WG "Biological Control", because biological control appears to be one of the most promising control strategies for parasitic weeds;
WG "Germination and Early Growth", because the first stages of growth of parasitic plants are fundamental for the success of parasitization and most susceptible for control;
WG "Weed Management Systems in Vegetables", because most of the parasitic plant species represent a serious problem in vegetables;
WG "Education and Training", because there is still a lack of knowledge regarding parasitic plants, their danger and the possibility of their management.

For more information and joining the Working Group please contact the coordinator: Maurizio Vurro,
Istituto di Scienze delle Produzioni Alimentari – CNR,
via Amendola 122/0,
70125 Bari, Italy.
Telephone: +39 080 5929331
Fax: +39 080 5929374;
E-mail: Maurizio Vurro