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insecticide up the trunk and into the branches I realize that I will have to protect my and canopy. When EAB larvae feed, their gal- ash trees from EAB for several years. Is leries injure the phloem and xylem that make it worth it? up the plants circulatory system. This inter- The economics of treating ash trees with feres with the ability of the tree to transport insecticides for EAB protection are com- nutrients and water, as well as insecticides. As plicated. Factors that can be considered a tree becomes more and more infested, the include the cost of the insecticide and injury becomes more severe. Large branches expense of application, the size of the trees, or even the trunk can be girdled by the larval the likelihood of success, and potential galleries. costs of removing and replacing the trees. Studies have also shown that if the canopy of Until recently, insecticide products had to a tree is already declining when insecticide be applied every year. A new product that treatments are initiated, the condition of the is effective for two years or even longer tree may continue to deteriorate during the (emamectin benzoate) has altered the eco- . In many cases, the tree nomics of treating ash trees. As research pro- canopy will begin to improve in the second gresses, costs and methods of treating trees year of treatment. This lag in the reversal of will continue to change and it will be impor- tant to stay up to date on treatment options. needed for the tree to repair its vascular system after the EAB infestation has been to quantify than costs. Landscape trees typi- reduced. cally increase property values, provide shade and cooling, and contribute to the quality of life in a neighborhood. Many people are sen- is quarantined for EAB. Should I start timental about their trees. These intangible treating my tree? qualities are important and should be part of any decision to invest in an EAB management Scientists have learned that ash trees with low program. densities of EAB often have few or no exter- nal symptoms of infestation. Therefore, if It is also worth noting that the size of EAB your property is within a county that has been quarantined for EAB, your ash trees are prob- over time. Populations initially build very ably at risk. Similarly, if your trees are outside slowly, but later increase rapidly as more a quarantined county but are still within trees become infested. As EAB populations 10-15 miles of a known EAB infestation, they reach their peak, many trees will decline and may be at risk. If your ash trees are more than die within one or two years. As untreated ash 15 miles beyond this range, it is probably trees in the area succumb, however, the local too early to begin insecticide treatments. EAB population will decrease substantially. Treatment programs that begin too early Scientists do not yet have enough experi- are a waste of money. Remember, however, ence with EAB to know what will happen that new EAB infestations have been discov- over time to trees that survive the initial ered every year since 2002 and existing EAB wave of EAB. Ash seedlings and saplings are populations will build and spread over time. common in forests, woodlots, and right-of- Stay up to date with current EAB quaran- ways, however, and it is unlikely that EAB will tine maps and related information at www. ever completely disappear from an area. That emeraldashborer.info. You can use the links means that ash trees may always be at some risk of being attacked by EAB, but it seems for individual states. When an EAB infesta- reasonable to expect that treatment costs tion is detected in a state or county for the could eventually decrease as pest pressure . declines after the EAB wave has passed. Note, however, that once an area has been quarantined, EAB surveys generally stop, and further spread of EAB in that area will not be . 4 INSECTICIDE OPTIONS FOR PROTECTING ASH TREES FROM EMEORER