Last weekend I was looking at apple trees near Detroit Lakes, Minnesota.  On one tree I noticed tiny caterpillars swarming the tips of two branches (Figure 1).  I also found egg masses on those same branches.  The larvae are forest tent caterpillar (Malacosoma disstria).  The mature larvae of forest tent caterpillar are easy to distinguish by the white, keyhole-shaped markings along their top sides (Figure 2).  The young larvae in Figure 1 don’t show those markings yet, though three days later, they are beginning to develop.

Controlling the insect was incredibly easy in this case – I clipped the ends off of three branches, removing the larvae and the egg masses (Figure 3).  However, if the infestation had been heavy, chemical control may have become necessary.  In such situations, Bt works well to control young caterpillars, while permethrin or pyrethrins or other insecticides are needed for older larvae.  As always, when using pesticides, follow label instructions carefully.

Figure 3. Egg mass of forest tent caterpillar

Once established, rhubarb plants will tend to produce seed stalks, flowers, and seeds each season. Cut the stalks as soon as the large pods appear at the base to allow energy to go into producing new leaves. If your rhubarb plant doesn’t produce seed stalks, don’t worry – it will eventually.

For more information on growing rhubarb, check out the NDSU Extension Service publication, "Asparagus and Rhubarb (PDF) ."

(Photo courtesy Satrina0)

Does your lawn have random patches of yellowing or other discoloration like the lawn in this photo provided by Todd Weinmann, Cass County Extension Horticulturist?

What to do? The best thing: wait 30 days and with normal weather temperatures rising, most will disappear. This is caused by a number of factors:

1. Soil being too wet or cold in those spots due to compaction
2. Juvenile roots – root system just kicking in
3. Previous season injury from grub feeding activity on the root system
4. Differences in green-up rates of different grasses
5. Obstruction to good root development due to tree roots or construction debris buried beneath the surface.
6. In some cases, iron deficiency being manifested due to high pH of soil or one of the reasons mentioned above.

What has bright yellow flowers, is loved by little kids, and hated by adults? Dandelions, of course! They are coming into full bloom this week, and depending on the daily temperatures, will go into seed that is easily air-borne in about 10-14 days.

If unwanted, as most are, especially in lawns, the question arises, what can I do to get rid of them? Here are some options, starting with the least favorite:

1. Dig them out – with all  the root – if possible. If as much as 95-98% of the root can be extracted, chances are that dandelion will not return. Garden center or garden supply stores will have tools that make this task easier and more successful.
2. If digging is unappealing, then pick up an RTU broadleaf herbicide that can be applied directly from the bottle with a sprayer that comes with the purchase. Wet the foliage only; no need to soak the plant. Within 24 hours or less, the effect of the herbicide will be evident, with the flower stem becoming curled and twisted.

This will usually result in the death of the plant. If not, revisit in a couple of weeks to administer another shot of herbicide.

Maintain the lawn properly to help prevent re-invasion from neighboring lots and properties: mow high 2.5” to 3”, fertilize during active growth at least twice a season – spring and fall - and water deeply and infrequently to encourage a deep root system.

(Photo courtesy code poet)

Description

Did you know that …

The flowers from littleleaf linden trees have a beautiful scent and are highly attractive to honeybees.

Boxelder trees are maples and their sap can be collected and boiled to make maple syrup.

Black Hills spruce is more resistant to needlecast and other diseases compared to Colorado blue spruce.

All this information and more is available in this 272-page book containing complete descriptions and full-color photographs on 66 tree species – 45 deciduous trees and 21 conifers – and 38 shrub species that are generally adapted to urban growing conditions in North Dakota.

Publication Number:

F-1309

Cost:

$12.50

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