Zeiraphera canadensis

Zeiraphera canadensis, the spruce bud moth, is a moth of the family Tortricidae. It is a small brown moth mainly found in North America, specifically New Brunswick, Quebec, and the Northeast region of the United States. The adult moth flutters quickly, and stays low among trees during the day and higher above tree cover after sunset. The spruce bud moth relies primarily on the white spruce tree as a host plant. Both male and female spruce bud moths mate multiply, however males have the ability to secrete accessory gland proteins that prevent female re-mating. The moth is univoltine, meaning only one generation hatches per year, and its eggs overwinter from July to May. The species Z. ratzeburgiana is very similar to Z. canadensis and can only be distinguished by the presence of an anal comb in Z. canadensis. In 1980, the moth was named a pest due to its effects on the white spruce tree’s growth. The spruce bud moth defoliates young white spruce trees, stunts tree growth, and deforms buds. Although the moth does not lead to spruce tree death, the deformation negatively affects the quality of wood harvested from spruce tree plantations. As a result, much research is being conducted into control methods for the spruce bud moth, including the use of sex pheromones in traps and annual pesticide sprays. The spruce bud moth is largely found in Canada, specifically New Brunswick and Quebec. The moth can also be found in other parts of North America and in the United States, particularly in the Northeast region, with high populations specifically found in Maine. The spruce bud moth is generally found in colder regions of the country, as their ovipositing and mating behaviors are highly temperature dependent. The spruce bud moth is named for its host plant and main habitat, the white spruce. The moth, transcontinental in range, is found most frequently on white spruce and only occasionally on other spruces and firs. The larvae of the spruce bud moth hatch in the buds of white spruce trees. Much of its development, adult life, ovipositing and mating occurs on this tree, making it a key aspect of the moth’s life cycle and habitat. Consequently, the distribution of the moth is limited to regions with high density of white spruce trees, such as Canada and other Northern temperate regions. Female spruce bud moths oviposit on the un-burst buds of a white spruce tree. Females test out potential sites to oviposit using sensillae on their ovipositor, a receptor on their feet. Studies have shown that on average, females lay just over 30 eggs total in their lifetime, and that ovipositing occurs approximately 6–7 days after they emerge as adults. The spruce bud moth hatches once a season, making it univoltine. The eggs are laid in July at the base of spruce shoots then hatch in May after overwintering. They are laid in clusters of up to 7 eggs. The moth has four larval instars. Upon hatching, larvae at first remain within bursting spruce buds. The first and second instar larvae feed inside the needles of the spruce, while the third and fourth instar larvae eat spruce shoots. This destroys the cortical tissue, leading to weakening shoots, tree height loss, and destruction of the crown of the tree over time. Larvae feed on the needles and shoots for up to six weeks before dropping to the ground, spinning silk from ground materials, and cocooning to pupate. The age of the bud can affect the survival of Z. canadensis, with older buds negatively impacting size and survival. The larvae of the spruce bud moth pupate in the end of May. The entire process takes 10 days to complete. When larvae develop into prepupae, they fall from the spruce bud shoot onto the ground and stay in that stage for 6 days. The moth pupates on the ground with its littermates.