Consider this an interim update on a “breaking news” plant health/plant pest issue. For several years we have been monitoring the situation with respect to box tree moth (Cydalima perspectalis), which in its larval/caterpillar stage, is an aggressive and damaging defoliator of boxwood (Buxus spp.). Ilex (hollies) and Euonymus spp. are also hosts. The pest, native to parts of Eurasia, was apparently transported to Western Europe via the nursery trade, and has been very damaging there. While relatively easy to control in nursery settings, it has significant negative impacts on boxwood in the landscape.

About two years ago, the pest was found in an urban neighborhood in Toronto. Control efforts have been undertaken, as has some degree of surveillance (including adult moth trapping using pheromone traps) in the nursery production areas in Ontario. USDA implemented a federal order requiring Canadian host plants to be inspected and certified free of the pest. Over these two years, we have pressured our Canadian colleagues (industry and regulators) to mount an aggressive effort to contain and eradicate the pest. AmericanHort and HRI have also contributed to the development and successful funding of two research projects to answer key questions about the pest’s life cycle and control options, in an attempt to get ahead of the curve should the pest be found to establish here.

Last week, we heard from USDA officials that the pest was found in a Niagara Peninsula (Canada) nursery. How it got there is not a sure thing, but there is a sense that the nursery was infested by the surrounding landscape, which suggests the problem may be of larger scope. Most concerning, this nursery shipped boxwood plants to 25 customers in 6 US states (MI, OH, NY, CT, MA, and SC, we understand as of now). State and federal officials are conducting trace-forward inspections at these destinations. We have little official information but informal report suggest the pest has been found on trace-forward plants in at least two of the states.

What’s next? While we are awaiting official word, it is our sense that USDA will revise its federal order imminently, and will likely prohibit all Buxus, Ilex, and Euonymus plants from anywhere in Canada, for some period of time while more information is sought to refine the approach. We know the folks in BC are particularly concerned, as they believe they are “far from the action.” But unless there is clear evidence from an ongoing surveillance program to bolster that position, we expect the order will affect all of Canada.

There was some messaging circulating in BC suggesting “if you have orders booked, ship right away before the border closes.” This was seen by the regulators, who as you can imagine did not react well, and we pushed back too. Canadian nurseries should NOT rush to ship, and US customers should NOT seek to receive orders to get ahead of APHIS emergency action. This is too high-consequence a pest for irresponsible trade practices. We do understand our Canadian sister associations have revised their messaging.