Posts tagged ‘insect’
By John Latimer, KAXE Radio, Grand Rapids
The last of the meadowhawk dragonflies will put in an appearance in early November. These small, bright red, insects are among the last to fly about in the fall. A warm day or two in the early part of the month will send them out in a last and probably fruitless search for other flying insects.
Flickr photo “Ruby Meadowhawk” by Jim Frazier. Original.
If you have been observing them throughout the fall you may have noticed them flying in tandem with the female periodically touching her abdomen to the grass. She is depositing eggs. Her strategy is to place her eggs on stalks of grass that will be inundated in the spring. Once awash the eggs will begin to develop and the larval stages will terrorize the shallow ponds and lake edges until late summer when they will emerge and terrorize the flying insects.
Those eggs mistakenly laid in the grass that may be your lawn will likely never develop. No one is perfect and least of all the meadowhawk dragonflies, but what they lack in foresight about those areas likely to flood they make up for in sheer numbers of eggs laid. Some of them will end up underwater and the species will survive.
Flickr photo “Dragonfly” by Chris Coomber. Original.
In the case of the meadowhawk dragonflies they survive the winter as eggs or larvae, but what about the Compton’s tortoiseshell or Mourning cloak butterflies? How do they survive the cold? They over-winter as adults and without an approach to overcome the cold they would freeze and die. For many insects the strategy is freeze avoidance.
There are three elements to freeze avoidance. First, the insect produces an anti-freeze which circulates in the blood. These special proteins bind with any ice crystals that may form keeping them small and preventing them from doing damage.
Second, they produce sugars and sugar based alcohols which act to lower the freezing point of any water in the body. These typically take the form of glycerols that by mid-winter may constitute 20 to 25% of the insect’s total body weight.
Flickr photo “Chionea species” by C Wood. Original.
The final part of a freeze avoidance strategy involves finding a dry location. Staying away from water and the resulting ice is imperative. Ice can act as a nucleator for the development of further ice crystals. The butterflies must find secure dry locations, other insects might construct waterproof cocoons or some other personal protection, but the butterflies lack this ability. This perhaps explains why I find so many of them in my garage.
John Latimer is well known throughout northern Minnesota for his phenology work. He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. His work is a frequent feature on MyMinnesotaWoods. This article also appeared in the Duluth Senior Reporter. It is printed with the author’s permission.
MDA survey finds 59 St. Paul trees infested with emerald ash borer
A multi-agency survey found 59 trees infested with emerald ash borer in and around the St. Anthony Park neighborhood where the pest was first discovered in May. All 59 trees are within a half mile of the first infestation site. Crews have already removed the 59 trees. Read the recent news release.
Monitoring efforts using purple cardboard traps and “trap trees” is underway.
Homeowners are asked to join the effort by watching their ash trees for signs of infestation. These signs include:
- dieback of leaves in the upper third of the tree’s branches
- heavy woodpecker activity
- D-shaped exit holes in the bark
- S-shaped tunnels under the bark
- water shoots on the trunk
Think you might have it?
If you think you might have Emerald Ash Borer use his checklist(pdf) to determine if you should get in touch with an EAB First Detector.
Minnesota Department of Agriculture Quarantine
On May 15th, 2009 the quarantine (previously applied to Houston) added Ramsey and Hennepin counties to prevent the spread of Emerald Ash Borer to new areas through the movement of infested wood and tree parts. Besides applying to all ash tree parts, the regulations apply to all non-coniferous firewood. Read more about the quarantine(pdf).
Don’t remove your healthy ash trees
MDA reminds homeowners that it is not necessary to remove healthy ash trees. Homeowners with questions about disposing of ash tree material should contact their city forester for guidance. Improper disposal of infested ash material could accelerate the spread of EAB.
What does EAB mean for the woodland owner?
Should you try to harvest your ash as quickly as possible? How should you manage your forest? Should you just let nature take its course? There are no simple answers to such questions, but the Michigan State University Extension put together a helpful publication to help woodland owners prepare for EAB.
For more information
By Steve Katovich, US Forest Service, St Paul, with contributions from Mike Reichenbach, University of Minnesota Extension
In 2002, a small emerald green beetle native to Asia was found killing ash trees in the Detroit area. The beetle was given the common name “emerald ash borer” or EAB for short. It had apparently arrived on infested pallet wood or crating material, perhaps as far back as the early 1990’s. The infestation spread undetected for 10 years. Surveys in 2002 quickly confirmed a massive infestation with almost every ash tree in the Detroit metro area affected.
Since then, EAB populations have been found in 10 states and 2 Canadian provinces. Of greatest concern is the transport of infested firewood from Illinois, north of Milwaukee, and in the Upper Peninsula of Michigan. By transporting firewood, visitors from these areas could very easily initiate EAB outbreaks here in Minnesota. Beetles could also arrive on an infested nursery trees or perhaps in logs arriving at a mill.
EAB is a tremendous tree killer, and Minnesota woods include a huge ash component in both rural and urban forests. In fact, EAB is proving to be such an efficient killer that it seems likely that few ash trees will populate our landscape in the future.
At this time, the best strategy is to delay EAB’s arrival as long as possible. Given enough time, researchers may yet uncover some key tools that will even out the battle between the insect and ash trees. Homeowners can help. Firewood should be obtained and burned locally. It is not a good practice to transport firewood long distances. Even within Minnesota it would be prudent to avoid transporting firewood from the Twin Cities to a cabin or campground. The Michigan experience has shown a number of state wide campgrounds were infested with EAB, as a result of firewood transport.
Despite our best efforts, EAB will eventually arrive in Minnesota. It would be best if any new introductions were found early. Everyone is encouraged to report unusual ash tree mortality. Extensive woodpecker activity on ash trees can be a sign that EAB larvae are active under the bark. This is most easily observed in the late winter when bark flakes cover the snow and the stripped bark stands out against a white background.
Minnesota landowners with ash do not need to panic. It will likely be years before EAB begins to impact Minnesota forests. But, it might be wise to rethink long term management plans for stands that have an extensive ash component. Rather than waiting for EAB to arrive, some early stand intervention could reduce the risk of extensive tree mortality. The insect attacks both healthy and weak trees, there’s little that can be done to create resilient stands. Landowners can take advantage of management actions planned in their woodland to harvest trees before the insect reaches Minnesota. After the insect is in MN quarantines may make it difficult to transport harvested logs.
Consider enrolling as an EAB First Detector. Trainings are coming up throughout Minnesota this spring. Details on upcoming trainings are on our class calendar and the Minnesota Department of Agriculture’s EAB website.
If you think you may have EAB on your property or in your woodpile, immediately contact the Arrest the Pest hotline: 651-201-6684 in the Metro Area or 888-545-6684 in Greater Minnesota. You can also email Arrest.The.Pest@state.mn.us.
Update: September 2009
Emerald ash borer (EAB), an invasive species, threatens to kill Minnesota’s ash trees. In response, Andrew David, a University of Minnesota forest genetics researcher, and Mike Reichenbach, forestry educator with University of Minnesota Extension, began a project to protect the genetic diversity of ash in Minnesota.
Seed collected from wild-grown ash trees will be sent to one of three seed storage facilities in Colorado, Georgia or Iowa depending on the amount of seed collected. This seed collection effort is a proactive response to the presence of EAB in Minnesota and the upper Great Lakes region. This conservation effort will preserve the genetic variation for a future point in time when EAB can be controlled and ash species can be reintroduced to Minnesota using locally adapted seed sources.
How to collect and contribute seed
Ash seed has been ripening all summer and will be ready to pick when the seed cavity is completely filled and the seed coat is brown. Collection of seed typically begins about September 21st and can continue through much of the fall. Black ash seed is the hardest to collect because it is difficult to judge ripeness and the seed begins to fall with the leaves. The best time to collect black ash seed is from 1 week prior to leaf fall to approximately 2 weeks after all leaves have dropped.
In contrast green ash seed will remain on the tree for awhile after the leaves have fallen allowing collections into late fall. It will be easier to collect from trees before the seed is scattered by winds and rain. Persons wishing to collect seed should watch the ash seed collection webinar found listed under the webinars tab at http://forest.nrri.umn.edu/ash. The ash seed collection form can also be downloaded here.
Value of ash to Minnesota; ongoing threat of EAB
Minnesota is host to three species of ash: white ash, green ash and black ash. While white ash is an upland species found along the Mississippi River in southeast Minnesota; both black and green ash are common lowland hardwoods found throughout the majority of the state. Ecologically, black and green ash are the most important hardwoods in the lowland forest community. They represent 51 percent of the lowland hardwood cover type in Minnesota. Black ash is very important in native cultures as a source of wood for ash baskets. Both black and green ash provide a source of pallet, saw and veneer logs. All of Minnesota’s native ash species are threatened by EAB.
EAB was most likely introduced to the region when it was transported on wood packaging of an overseas shipment from Asia in 2002 to the Detroit, Michigan and Windsor, Ontario area. Within the United States the insect is most often transported on firewood. As of August, EAB has been found in Illinois, Indiana, Maryland, Michigan, Missouri, Ontario, Ohio, Pennsylvania and Wisconsin. It has been responsible for the death of over 20 million ash trees despite quarantines on moving nursery stock and firewood out of infected areas.
This conservation effort will preserve the genetic variation for a future point in time when EAB can be controlled and ash species can be reintroduced to Minnesota using locally adapted seed sources.
Click for much more information on emerald ash borer in Minnesota. To get involved in seed collection, contact Mike Reichenbach, (888) 241-0724, email@example.com; or Gary Wyatt, (888) 241-3214, firstname.lastname@example.org, both with University of Minnesota Extension.
A review of categories of insects affecting tree and forest health: Defoliators, borers, sap-sucking insects, root-feeding insects, cone- and seed-destroying insects, and non-native invaders.