Milkweed Tussock Moth

Milkweed Tussock Moth

Tom Ingram: Ask A Master Gardener

Sunday, September 15, 2019

Q: I grow milkweed in my garden for the migrating monarchs, but there are some fuzzy caterpillars that are black, orange and white devouring my milkweed. What are they and what should I do about them? MC

A: Monarch butterflies are often in the news. We hear about their dwindling population, and many people are planting a variety of plants to support them on their migration to and from Mexico. Milkweed is the sole source of nutrients for monarch caterpillars. However, what you are describing is another insect whose caterpillars also prefer milkweed: the milkweed tussock moth.

Female milkweed tussock moths lay their eggs in white masses on the underside of milkweed leaves starting in June. When the eggs hatch, they begin feeding and may go unnoticed for a while.

By their third instar (a phase during the developmental process), they become these unique and beautiful fuzzy caterpillars with tufts of black, orange and white. The adult moths are not nearly as stunning, but many of us have been told we were better looking when we were younger so…

If the female moth laid all her eggs in one spot, what starts as a kind of mob feeding thins out as the larger caterpillars spread out and move to other milkweed plants. At the point they are in full tufts mode, they tend to feed alone or in pairs.

Soon, they leave the milkweed plants to form a cocoon in which they pupate. Farther north, there is only one generation per year, but in our area, two generations per year are not unusual.

Bats are the primary predators of moths; however, the milkweed tussock moth tends to be immune from being fed upon by bats because they produce an ultrasonic click from what is called a tymbal organ. Bats recognize this sound and avoid them because they are not interested in a toxic meal. The moths are toxic (like monarchs) because their favorite food (milkweed) contains a poison called cardiac glycosides (cardenolides). Being toxic is a great way to get predators to leave you alone.

The caterpillars are voracious eaters and can decimate your milkweed plants, so, if found, you have a decision to make. Because you said you grow milkweed for the monarchs, you might consider the milkweed tussock moth an unwelcome interloper. Or perhaps you can just embrace the idea that you were growing caterpillar food, which is serving its intended purpose, just not in the way you had planned.

If the live-and-let-live philosophy doesn’t work for you, you will want to remove the milkweed tussock moth larvae. Physical removal would be best as any chemicals you might use could work to the detriment of your monarch sanctuary.

As for me, the photo of the milkweed tussock moth seen here is from my garden. I didn’t enjoy seeing my milkweed disappear before any monarchs found it, but I decided to enjoy and appreciate the milkweed tussock moth’s beauty while hoping they leave something for the monarchs. Maybe you will, too.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Garden tips

·        Watch for fall specials at garden centers and nurseries because fall is a great time for planting many ornamentals. Choose spring-flowering bulbs as soon as available.

·        Fertilize established fescue lawns with 1 pound of actual nitrogen fertilizer per 1,000 square feet now and again in November. Do not fertilize Bermuda or zoysia lawns until next spring. Late fertilization of these warm-season grasses may promote disease.

·        September and early October is garlic-planting time with an aim for harvest in June of next year. There are many varieties from which to choose. OSU suggests German Red, Inchilium Red, Silverskin and Spanish Roja for varieties that do well in our area.

·        Remember, our Fall Lunch & Learn classes will be starting Tuesday, Sept. 17. You can find more information and topics on our website.

Fall Is The Time To Reseed Tall Fescue Lawns

Reseeding Tall Fescue Turfgrass

Brian Jervis: Ask A Master Gardener

Sunday, September 1, 2019

Q: I understand that fall is the best time to reseed with fescue. However, I am not sure how to do it and what type of seeds to buy. Can you help me? Robert T., Broken Arrow

A: Fescue is called a “cool season” turf grass for a reason. It does not tolerate hot weather well at all. We have just had a big dose of heat, and there are many brown patches in Tulsa’s fescue lawns that need reseeding. The good news is that it is about time to do so. The ideal time for sowing cool-grass lawn seed is from mid-September to mid-October. It is also generally recommended that a soil test be performed before reseeding to determine what nutrient amendments might be needed. Therefore, right now would be a perfect time to do this because there is time to get your soil test results back before time to reseed.

If weeds and/or Bermuda grass are present, spray the planting area with a glyphosate product. Two spray applications will be needed to fully eradicate Bermuda grass. One week later, the dead weeds and grass can then be raked and removed.

If the soil is compacted, it will need to be tilled (either by machine or by hand) to be receptive to the seed. A starter fertilizer, along with any amendments you might wish to use (e.g., organic compost), should be added at the time of tilling.

Read the label directions to sow the proper amount of seed to get good coverage, but avoid excess seeding. More is not better. After sowing, the top of the soil needs to be kept constantly moist (not wet) until seedlings are 2 inches tall. Then, change to less frequent and deeper watering to encourage deep roots. While there are no guarantees, this will help to improve the sustainability of fescue through the hot summer months. The grass should be mowed with a sharp-bladed mower after reaching a height of 3 inches. Another application of a nitrogen fertilizer should be made in November.

One of the common issues in reseeding cool-grass lawns is deciding what type of grass seed should be used. Unfortunately, there is not one that is bulletproof, and no one single fescue variety stands out as the best overall. Each fescue variety, individually, has its own strengths and weaknesses. Therefore, it is recommended that a mixture (two or more species) of fescue, Kentucky bluegrass and perennial rye grass be used to cope with various diseases. Another appropriate choice is to use one of several mixtures of tall fescue without the other turf grass seeds. Any of these mixtures will perform well and will be better than a single type of fescue alone.

One thing is clear — we live in a difficult area to grow cool-season grasses. Detailed instructions for lawn seeding are available in OSU Fact Sheet HLA-6419, “Establishing a Lawn in Oklahoma.”

Garden tips

• Always follow directions on the labels of synthetic and natural pesticide products. Labels will always list where the product may be used and which pest it is certified to cover. If you do spray pesticides, do it early in the morning or late in the evening after bees have returned to their colony.

• If your tomatoes are too tall and gangling, now is a good time to prune the top of the plants by as much as ⅓ to ½ depending on the plant. This will stimulate new limb growth and new fruit production after it cools.

• Tall fescue should be mowed at 3 inches and up to 3½ inches if it grows under heavier shade. Do not fertilize fescue lawns until it cools in September, then fertilize once again in November. Do not fertilize in the summer.

• Now is a good time to submit a soil sample to the OSU Extension office for testing. Do this before reseeding fescue or creating a garden bed this fall. You can call the Master Gardener office at 918-746-3701 for instructions.