Q: I have a big patch of daylilies that has been great over the years, but now gets yellowish and crinkly leaves that dieback. I thought it was dry weather last summer and they came back in the fall. Now it is starting again. The symptoms match "leaf streak," and the recommendation I find is to spray with a fungicide with mycobutanil. Will that fix it?
A: Spraying the lilies with a broad-spectrum fungicide like Spectrum Immunox (active ingredient mycobutanil) won't hurt anything and should help. The fungicide may need to be used several times, and prevention is easier than curing (now that symptoms are present). Using during wet spells is especially important. Cultural activities are also important, such as removing dead leaves from your daylilies each fall to eliminate a source of the leaf streak fungus. As your daylily plants grow, divide them into smaller clumps and replant them with ample space between clumps. This will improve air circulation and promote more rapid drying of leaves. Some cultivars are most resistant to the disease than others. Be sure to read and follow fungicide label directions.
Q: I missed putting down nitrogen fertilizer on my cool season lawn back in March and April because it was so cold. I'd like to give the grass a boost, what might I do?
A: Put a typical lawn fertilizer on at half the normal rate. A turf fertilizer rate advised on the bag should be for 1 pound of nitrogen per 1,000 square feet, so you would be applying pound of nitrogen instead. You turf will get a boost and hopefully it won't overly stimulate its growth.
Q: I get this lawn weed every year that gets little nut-like seed heads later in the summer. I think I see it starting now. Is this a good time to get on top of it?
A: Yes! The weed you describe is almost assuredly yellow nutsedge (some folks call it 'water grass' as it thrives in wetter areas). The key to controlling it is applying a herbicide when it's smaller (two to four leaves). Many people wait until they see the "nutlets," and this is latter than desired. A good product is Sedgehammer, but it does need to be mixed up and applied as a spray. Be sure to read and follow the herbicide label directions.
Q: I have carpenter bees that are getting into my deck. It started with just a few last year and now there are a bunch and they are getting annoying. Do I have to kill them? I thought they were pollinators, thus good. And how do I prevent them from returning. My deck is painted, but it's been a while.
A: We have a publication dedicated to this insect: extension2.missouri.edu/g7424. Please read the management section. It is advised to treat the holes with insecticide (twice) if their mating activity has started (which it has). Then chalk/fill holes or damage and paint. Paint deters them, but as the paint ages, is less effective. Once they like an area, the newly hatching ones are likely to return there, so their presence can quickly increase. They are a beneficial pollinator when living on deteriorating wood in a natural setting or on structures that no one cares about, and (in that situation) help to recycle wood.
Q: I got a new security light that is an LED. Now June bugs are showing up dead under the light in the morning. I know the LED is brighter than the last light, but I thought LED's were safer to insects, as they're cooler. Should I feel bad for the June bugs?
A: Don't feel bad for the June bugs, they are a lawn pest that survives in high numbers, like Japanese beetles. They just feed at night, so you don't see them. Many insects are attracted to lights, and a higher brightness would attract more strongly, that is known. The spectrum of the light given off from the source (LED versus incandescent) may have an effect on attractiveness. One study found a majority of insects have a preference for blue wave length, but some insects preferred red, white or yellow. Interestingly, LED lights have more blue than incandescent, so maybe June bugs are in the group of insects preferring blue wave length. LED lights are cooler, so wouldn't 'scorch' insects as bad, thus might be perceived as safer. Lastly, ultra-violet lights are used in specific applications to attract certain insects (e.g. flies) to be "zapped," which further complicates this discussion.
For an informative, yet somewhat flippant read on the subject, check this web posting: luxreview.com/article/2015/06/-led-lights-don-t-attract-insects-true-or-false-.