By Ruth Vaughan
Duponchelia fovealis, aka the European Pepper Moth, is an emerging pest in our Kenyan greenhouses. This may be due to the reduced use of harsh chemicals. You can often see the adults as you wander through the greenhouses, when disturbed they fly out of the plants. The adult moth is brown and white and relatively nondescript, being fairly small with a wingspan of under an inch. Most of us ignore them!
The nondescript adult Duponchelia Duponchelia populations are widespread and emerging throughout the World, although some countries still classify them as a quarantine pest, many have discarded their regulatory actions. The list of plant species attacked by Duponchelia is long with more than 70 host species in numerous plant families. The level of economic Ring barking of plants at ground level due to feeding of Duponchelia larvae – this kills plants damage that they can cause has not yet been quantified.
Why are they dangerous?
The adult moths lay their eggs on the underside of bottom leaves, and in plant debris. The eggs are single, tiny and difficult to see. The larvae are minute on hatching and grow to a maximum of an inch, they are a creamy white with a black head and spend most their time underground. They feed on soil detritus, bottom leaves, stems, fruits and roots depending on the crop. In
roses they feed on the crown of the plant, where the stem goes into the soil.
The damage is impossible to see unless you dig. They can effectively ring bark plants at soil level. This creates entry wounds for exploitive diseases, most notorious of these is Agrobacterium. (In addition to this the Duponchelia larvae is very partial to feeding on decaying Agrobacterium galls.)
The insect-disease complex caused by Duponchelia feeding damage in association with disease spores at its best causes a big reduction in quality and production and at its worst kills plants, costing growers lots of money.
How to control and monitor Duponchelia
Controlling Duponchelia is cheap and easy compared to the damage they do, and can be completely biological, in addition to reducing thrips and fungus gnats at the same time! It’s a -win:win. Monitoring of the adults using Duponchelia pheromones and insect traps can also be used to trap and reduce populations. Remove crop debris and lowers leaves to reduce habitat.
Duponchelia love a moist humid environment. BT’s, predatory nematodes (e.g. Steinernema), EPF’s (e.g. Beavaria bassiana) are effective as sprays and drenches. Parasitoids (e.g. Trichogramma) and predatory mites (e.g. Hypoaspis). If the worst comes to the worst you can always spray chemicals registered for Lepidoptera, but the larvae are so inaccessible it’s best to leave the good bugs to do all the hard work.
Ruth Vaughan is the Technical Director at Crop Nutrition Laboratory Services Ltd. (CROPNUTS). Ruth is also a contributing author to Kenya’s leading horticulture magazines such as the HortFresh Journal, HortiNews and Floricu