First present in the USA in 1879, Zimmerman pine moth (Dioryctria zimmermani) is a small grey insect with zigzag strains of purple and grey and a wingspan of 1 to 1½ inches. The grownup moths are not often seen, as they’re energetic solely at night time. Females lay 20 to 30 eggs which might be cream coloured at first after which flip brown as they develop. These are laid beneath the bark close to the injuries created by their boring into the tree. When hatched, the larvae develop into brown-headed ¾-inch-long caterpillars with our bodies that modify from pink to inexperienced and are lined with black spots. Wintering over on the finish of tunnels bored beneath the bark, they emerge in late spring to proceed their life cycle.
Which Midwest conifer species are inclined to Zimmerman pine moth?
Zimmerman pine moth (ZPM) has grow to be one of the crucial economically harmful pests of conifers within the Midwest. It causes extreme harm to most pine species (Pinus spp., Zones 2–11) within the north central a part of our nation and likewise is thought to infest spruce (Picea spp., Zones 2–9). Conifer species which might be generally grown in our space and inclined to ZPM embody the next:
- Norway spruce (Picea abies, Zones 3–8)
- Black hills spruce (Picea glauca var. densata, Zones 3–6)
- Colorado spruce (Picea pungens, Zones 2–8)
- Jack pine (Pinus banksiana, Zones 3–8)
- Swiss stone pine (Pinus cembra, Zones 3–7)
- Lodgepole pine (Pinus contorta, Zones 6–8)
- Mugo pine (Pinus mugo, Zones 3–7)
- Austrian pine (Pinus nigra, Zones 5–8)
- Western yellow pine (Pinus ponderosa, Zones 5–8)
- Pink pine (Pinus resinosa, Zones 3–7)
- Japanese white pine (Pinus strobus, Zones 4–9)
- Douglas fir (Pseudotsuga taxifolia, Zones 5–7)
What does a Zimmerman pine moth infestation seem like?
Early proof of a ZPM outbreak is often the wilting and browning of recent development. Terminal branches which might be infested flip downward right into a shepherd’s-crook form. If untreated, the department will finally die and break off. Relying upon the dimensions of the tree, this can be the highest of the tree or a aspect department. Sometimes, ZPM assaults bushes above eye degree, which makes detecting them troublesome earlier than harm is seen.
What ought to I do if Zimmerman pine moth is in my space?
If you’re conscious of energetic ZPMs within the space, you possibly can establish their presence earlier than vital harm is completed by searching for proof of their bore holes. They like to assault both at or under the spot the place whorls of branches lengthen from the trunk, and much of soppy resin, white with sawdust or caterpillar waste, point out an energetic infestation web site. These moths seem to have a desire for bushes with wounds, which might be unhealthy or careworn, or which have been infested earlier than.
Controlling ZPM begins by offering your bushes with the perfect rising setting potential. Within the panorama, provide sufficient quantities of water and apply mulch to take care of soil moisture. If regardless of your finest efforts to maintain your conifers wholesome ZPM reveals up, there are not any pure or natural strategies to manage it. Three pesticides have been proven to be efficient in managing them. Of the three, just one is obtainable in retail shops–Permethrin—which is the energetic ingredient in Hello-Yield Turf and Termite in addition to Decorative 38 Plus. Earlier than making use of any chemical controls, make sure to learn the label and comply with the directions. The opposite merchandise, Chlorantraniliprole and Bifenthrin, ought to solely be utilized by an authorized skilled.
With the life cycle of ZPM there are solely two intervals of time when the caterpillars are outdoors of their tunnels, making these the best occasions to spray with pesticides. Sprays will be unable to succeed in the caterpillars as soon as they’ve returned to the tunnels. The primary time to spray is when caterpillars which have wintered over start to emerge within the spring. Relying upon the climate, that is sometimes someday in April. The second time when spraying is efficient is late summer season when eggs are being laid and hatching. This could happen in late July by August.
ZPM has been confirmed to be extremely harmful in each residential and business landscapes. Because of its aggressive nature, business tree farms must be extra ruthless of their controls by eradicating contaminated bushes as rapidly as potential to cease the unfold. Early detection and motion can cut back the necessity for eradicating bushes within the house backyard. Make it a behavior to watch your plant materials for anomalies and discolorations that might point out a pest has taken up residence. When vital, seek the advice of your native horticultural professionals or on-line assets for assist to establish the issue and the suitable plan of action, and report your discovering to your native cooperative extension service for affirmation and to assist forestall the unfold. With vigilance and therapy, most issues will be overcome, however not all.
—Marti Neely, FAPLD, owns and operates Marti Neely Design and Associates in Omaha, Nebraska.