Duponchelia fovealis - pronouncing it is just the start of the battle

A small nondescript moth has become the latest in a long line of exotic pests and diseases to cause the industry grief after being found in Ontario for the first time in three greenhouses in the spring of 2005. This moth has no common name, only the scientific one as given in the title. The insect is native to the southern Mediterranean and the Canary Islands, but in the last 20 years has been found increasingly in greenhouses in more temperate areas of northern Europe. The Canadian infestations are thought to have been introduced on imported plant material, and while they can survive happily in the greenhouse, they would not survive outside during the Canadian winter.

The moth has a broad host range and can affect crops such as begonia, gerbera, cyclamen, anthurium, kalanchoe , poinsettia, and rose as well as many other crops, including aquatic plants, corn and greenhouse vegetables such as peppers. The caterpillar stage of this pest likes moist conditions and lives low down in the plant, close to the soil line, feeding on the base of stems and the crown. In some crops such as roses, it will feed primarily on crop debris such as fallen leaves.

The adult moth is greyish brown and about 10-12 mm long. It has a long slender abdomen upturned almost at right angles at the tip. It flies mainly at night, although it is also easily disturbed in the day. In these situations it makes short erratic flights, before settling down again in the crop. The caterpillars are cream to brown coloured, 20-30 mm long when fully developed, and often spin webbing in and around the base of the plants. The larvae spin a cocoon in which to pupate, incorporating bits of soil and other debris which make them difficult to detect. The life cycle from egg to adult takes 6-8 weeks depending on the temperature.

The economic importance of these pests is twofold. Firstly, they can cause considerable damage to plants by feeding on leaves, crowns and stems, and also by boring into the stems of some plants. In vegetables such as peppers, they can also bore into the fruit. In some crops such as roses however, a large population can survive on plant debris without causing significant crop damage. Secondly, and probably more importantly, the presence of the moth can lead to trade restrictions for any crops grown for export to the US. Duponchelia is not established in North America and is listed as a pest of quarantine significance. It has been intercepted on many occasions on plant material entering the US from The Netherlands, most often on greenhouse peppers, resulting in the rejection or destruction of the shipment. The same fate would await any interceptions from Canada. The implications for the individual grower and for the industry as a whole could be devastating.

Fortunately for the three growers in Ontario found to be infested, an agreement was reached that allowed each of them to continue harvesting and shipping product provided that certain conditions of crop management were met. These conditions of sanitation, inspection and harvesting were designed to eliminate the risk of moving any Duponchelia life stages out of the greenhouse with the shipped product. At the same time, control measures were put in place to eradicate the pest.

So what are the control options? Needless to say, when a new pest is found in Canada for the first time, there are unlikely to be any pesticides specifically registered for its control. In this type of situation where rapid registration of pesticides is needed, a process called Emergency Use registration comes into play. The PMRA working cooperatively with the Canadian Food Inspection Agency (CFIA), the Ontario provincial government (OMAFRA), and industry (Flowers Canada) expanded the labels of three existing products in a time period of 2-3 months. DDVP (dichlorvos) smoke fumigators and Pounce (permethrin) are now registered for the control of adult Duponchelia moths and Dipel (Bacillus thuringiensis) is registered for control of the caterpillars. For anyone aware of how long a normal pesticide registration takes, this is an excellent example of industry/government cooperation. The affected growers are currently in the process of an eradication program which is being monitored by CFIA.

There may be some growers who are considering preventative spraying for Duponchelia using the above pesticides. There are a couple of points to bear in mind. Firstly, excessive and unnecessary spraying can lead to greater potential for worker health and exposure issues, and with disruption of biocontrol or IPM programs. Secondly, if Duponchelia is present or suspected and a control program is not carried out under CFIA direction, then it will be difficult to know if eradication is achieved. A grower may think he has eradicated a population only to find later that a residual population re-emerges as a major problem.

It is important for growers to understand that they have an obligation to report any suspected findings of Duponchelia to CFIA. Although the implications for the individual grower may be serious, there may be even greater implications for the industry as a whole if the pest becomes established. Timely reporting of new introductions allows us the best opportunity to eradicate. Unfortunately, given the nature of the ornamentals industry and the widespread movement of plant material around the world, introduction of new pests and diseases is inevitable from time to time. This is just the latest in a long line of introduced pests and diseases that the industry has had to deal with, and almost certainly it won't be the last.

Figure 1. Duponchelia adult. Photo: Central Science Laboratory, UK

Figure 2. Duponchelia caterpillar. Photo: Central Science Laboratory, UK