ICARDA Caravan 16

ICARDA scientists and their partners in research for development have come up with integrated management approaches to combat Sunn pest, a very damaging insect affecting wheat and barley production, especially in the highlands. Some options for Sunn pest integrated management are ready for extension to farmers, but success will depend on a policy move away from reliance on chemical pesticides.

Sunn pest (Eurygaster integriceps, Puton) is a very destructive insect pest of wheat and barley in Syria, Iraq, Iran, Turkey, Afghanistan, and Lebanon, as well as in Central Asia and the Caucasus, Bulgaria, and Romania. Both nymphs and adults cause damage to plants and reduce yields and quality by feeding on leaves, stems, and grains. Apart from the direct reduction in yield, the insects also inject chemicals that greatly reduce the baking quality of the dough. If as little as 5% of the grain is affected, the whole grain lot might be rendered unacceptable for baking.
Sunn pest infestations, which can lead to 100% crop loss in the absence of control measures, affect about 15 million hectares annually. About US$40 million is spent each year on pesticides. For example, about 1.5 million hectares in Turkey and Iran, 240,000 in Afghanistan, and 200,000 in Syria are sprayed against the pest. In addition to the high cost of chemical control, insecticides pose a risk to nature’s balance, human health, water quality, wildlife, and the

environment as a whole. The present insecticide-based strategies must be replaced with multi-dimensional integrated pest management (IPM) approaches. In collaboration with its partner national agricultural research systems, along with the University of Vermont, USA; CABI Bioscience; and the Natural Resources Institute, University of Greenwich, UK; and with support from the United States Agency for International Development; the Conservation, Food and Health Foundation, USA, and the Department for International Development, UK, ICARDA is developing IPM options for the

management of Sunn pest making use of egg parasitoids, entomopathogenic fungi, host plant resistance, sex pheromones, and cultural practices, such us adjusting planting date and use of early maturing varieties.
Work on egg parasitoids has involved surveys to identify parasitoid species in Sunn-pest-prone areas and estimating the level of parasitism. Several species have been identified that seem to have a big role in reducing Sunn pest populations. The level of parasitism can reach 90% or more by the end of the growing season. Conserving these natural enemies is our challenge, and one way to achieve that is through the rational use of pesticides. Pesticides that are less harmful to natural enemies are used, and only when necessary, once the economic threshold is reached.
More than 300 fungal isolates have been collected from Sunn pest overwintering sites in West and Central Asia; this represents the largest collection of Sunn pest entomopathogenic fungi worldwide. Based on laboratory and greenhouse bioassays and preliminary fieldwork, several isolates have shown great potential for use as biocontrol agents. Work on formulation is underway and more field tests will be conducted next season, including some limited tests of these materials at IPM pilot sites to be established in farmers’ fields in Syria, Iran, and Turkey.

A methodology for screening germplasm for resistance to Sunn pest using artificial infestation in field cages has been developed. Several bread and durum wheat lines and wild relatives have been found that are resistant at the vegetative stage. These sources of resistance have been given to breeders for use in their programs.
The IPM options will be extended to farmers through a participatory approach using farmer field schools formed around each of two IPM pilot sites in Syria, Iran, and Turkey starting next season. The biggest challenge in implementing IPM for Sunn pest management is national agricultural strategies that rely on chemical control. The cost of chemical control is borne by governments. So faced with Sunn pest infestation, farmers apply pressure to their political representatives, who in turn request the government to spray. Until policy is changed to devolve the insect control responsibility to farmers and remove the

disincentives for adopting IPM as an alternative to agrochemicals, it will be very difficult to make significant progress in IPM. Public awareness and education at the level of public institutions, farmer organizations, and farmers are crucial for the success of such policy change. Studies assessing the potential impact of IPM options are an integral part of this research. The results should provide policy makers with important information on which to base their decisions.

Dr M. El Bouhssini and Dr R. Canhilal are Entomologists, and Dr A. Aw-Hassan is an Agricultural Economist, at ICARDA.