UMass Extension Landscape Message June 6, 2014

"Winter Moth caterpillars have ceased feeding for this year and are now all in the soil, mostly under host plants, and have pupated. Adult moths will begin to appear around mid-November but they do not feed in that stage. There are no control measures that can be implemented now. As reported by the Elkinton Research Lab at UMass, Winter Moth appeared in MA and Rhode Island this year in substantial numbers, overall. Rhode Island, in particular, was hard hit by defoliation from this pest. Damage to host plants varied by region in MA this year. Defoliated trees should be monitored throughout the rest of the growing season. Deciduous trees, in general, should re-foliate but most of the foliage needs to be lost for this to occur. Trees that suffered less than 70% defoliation may not have lost enough foliage for re-foliation to occur. In either case, the loss of any foliage is significant to the overall health of the tree. Fertilization of injured trees is not recommended but watering during dry periods can be essential for the survival of the tree. Trees that have experienced repeated defoliation in successive years are at extreme risk. Three consecutive years of defoliation can result in the death of the host tree."

"Lily Leaf Beetle adults remain active but now we are seeing more eggs and feeding larvae. Larvae, which began appearing earlier this week, are easily treated with a product that contains Spinosad. Adult female beetles lay their eggs on the undersides of leaves in jagged lines that are about one inch long. When monitoring for eggs, stand next to a plant and gently fan the foliage upwards to visually inspect the leaf undersides. Make note of small, irregular lines of tan eggs that will be quite apparent on the fresh new lush green foliage. In small planting, leaves with eggs can be physically removed and destroyed. In larger plantings, continue to monitor. The eggs will turn orange and then a deep shiny red just prior to hatching. Treat new larvae with a product that contains Spinosad."

Claire