Burning turf We are looking into changing the work hours of our grounds crew to 6 a.m. to 2:30 p.m. instead of 8 a.m. to 4:30 p.m. We find that in the heat of the afternoon sun, when it's about 85 degrees to 100 degreesF, the grass tends to burn. If we mow earlier in the day, could there be less damage to the grass?-Saskatchewan
Yes, that could be true. The problem is not the heat, per se. It's the fact that turf often becomes stressed in hot weather, especially when it lacks adequate water and is more susceptible to physical damage from mowers in its stressed condition. According to Dr. Tom Watschke of the Pennsylvania State University, this is due to a lack of turgor, which basically means that the plants are wilting. In this condition, the grassplants cannot physically withstand wear as well, and both mower wheels and the action of mower blades can damage them. If you shifted your mowing to earlier in the day, it's possible that the turf could be under less stress at the time of mowing because temperatures would not be as hot. The result could be less damage to the turf.
If you are in a situation where mower noise early in the morning could offend some people, this might not be the best option. Regardless, an even better solution, explains Watschke, is simply to stay off turf that is under serious heat stress until conditions improve. Obviously, irrigated turf is not as prone to this problem because it isn't exposed to so much water stress. However, for turf where irrigation is not available, it's best to stay off it altogether until cooler or wetter weather returns. This usually is not a problem because the turf won't be growing until more water is available anyway.
Low-maintenance plants What are some possible low-maintenance plants for Northern and Central California?-California
People typically think of "low maintenance" as meaning that the plant will more or less take care of itself after you put it in the ground. In arid regions (which comprise much of California), this means that the plant must be able to survive with little or no irrigation. However, "low maintenance" also can mean several other things, such as pest and disease resistance, or slow rate of growth or spread (for example, invasive plants are not good low-maintenance choices). Therefore, "low maintenance" means any characteristic that significantly reduces the amount of effort a plant requires to succeed in a particular setting.
Regarding drought tolerance, a good way to develop a palette of such species is to consult a reference on California natives. One good resource is Growing California Native Plants, by Marjorie G. Schmidt (University of California Press, Berkeley, Calif.). Another is Native Shrubs of California, by Glenn Keator (Chronicle Books, San Franscisco). Many California natives are adapted to the arid climates that predominate throughout much of the state and therefore do well in unirrigated landscapes.
However, one thing you will find (the hard way, if you're not careful) is that many xeric-type plants not only tolerate summer drought, they demand it. For example, many California natives adapted to dry summers are notoriously susceptible to lethal soil-borne fungi in irrigated landscapes. You almost have to keep them in an unirrigated landscape, or at least in an extremely well-drained spot.
Some advocates of native plants claim that exotic ornamentals are generally prone to more problems because they are growing in an environment to which they are not adapted. In reality, however, artificial landscapes are alien to practically all plants. Therefore, it's not really that useful to generalize about a plant's adaptability based simply on whether it's native to the region. You must take each species as an individual case. To get the best balance of good performance with minimal maintenance, you need to do three things:
First, carefully choose plant species based on known resistances and adaptations that match your region and climate, and the conditions of the specific site where they'll grow, including water, soil, light and drainage conditions, and prevalent pests.
Second, try to create entire plantings with similar cultural requirements-mixing species with diverse requirements means that whatever maintenance regime you use will inevitably be unsuitable for at least some of the plants.
Finally, follow through and actually provide maintenance that matches the needs of the planting, such as a dry landscape for xeric plants and a wet one for water-lovers.
Red thread What are the best treatment and prevention techniques for red thread?-Ohio (via the Internet)
Red thread, most prevalent in spring and fall, affects several turfgrass species-mostly cool-season types and especially perennial ryegrass. It tends to be more severe when fertility is low, so turf managers think of it as a low-nitrogen disease. However, it's the turf's growth rate that is the important factor. Higher nitrogen fertility discourages the disease because it increases the turf's growth, helping it "outgrow" the disease. Cool, damp conditions favor the pathogen, and slow growth from low-nitrogen fertility or cool soil temperatures increase the severity of the disease.
Many superintendents find that increasing nitrogen rates is successful in reducing red-thread incidence, and it's certainly worth trying. However, you must consider other problems that could occur as a result. For example, some diseases that are more destructive than red thread can increase with higher nitrogen, so the cure could be worse than the original problem.
In spite of the success some superintendents have had with increasing nitrogen rates, many experts recommend a conservative approach of keeping fertility at typical levels and simply using fungicides when red-thread outbreaks occur. Numerous fungicides control red thread, so chemical-control options are plentiful.
Be sure to use good cultural practices that minimize turf stress and encourage vigor, and keep periods of leaf wetness as brief as possible (irrigate in the morning). Collecting clippings may reduce the spread of the "threads" (stromata, technically speaking) compared to returning clippings to the turf.
Though cultivars may vary in their degree of red-thread resistance, you probably wouldn't be wise to select a variety on that basis alone. Red thread is not usually the most serious problem in a given area, so other cultivar characteristics should take priority.
Aside from treating for ticks in a limited area around a property, you can do little to control Lyme disease. Part of the problem lies with the fact that deer ticks, which vector Lyme disease, spread wherever their hosts roam. Not only do deer carry deer ticks, so do several other common mammals that can range over large areas. Thus, controlling the ticks means controlling the animals-not an easy matter. Fortunately, U.S. Department of Agriculture (USDA) scientists are developing alternative treatments and techniques that may help curb the deer ticks that carry Lyme disease. * Nematodes. Steinernema and Heterorhabditis nematodes, better known for their ability to control insect pests, also attack ticks. A USDA scientist, Dolores Hill, is looking at the effectiveness of these infectious nematodes at controlling ticks, with hopes that she can ultimately find a way to establish them in the outdoor environment, providing long-term control of the ticks that carry Lyme disease. Interestingly, the nematodes mostly infect blood-engorged adult females. The reason appears to be that the swollen females' natural body openings offer entry points for the nematodes.
Hill now plans to explore outdoor use of the nematodes by developing application techniques and studying the cold hardiness of the nematodes, which, after all, must be able to survive outdoors if they are to provide more than short-term control of ticks. * Fungi. A colleague of Hill, Patricia Allen, is working with fungi that naturally infect ticks. After isolating several fungi from ticks that died of natural causes, Allen now is testing the ability of the spores to infect live ticks. Ultimately, Allen hopes her research will lead to development of products that grounds managers can apply to leaf litter, shrubs and other landscape areas where ticks reside. * A new twist on chemical control. John Carroll, a USDA entomologist, is working with deer-feeding stations called "four-posters." Each four-poster consists of a bin of corn and four upright roller-applicators coated with the chemical amitraz. A deer cannot get to the corn without brushing against at least one roller, which then deposits the chemical on the deer's ears, head or neck. This system has been tested in Texas and provided up to 97 percent control of Lone Star ticks in studies there. Carroll hopes to attain similar success with deer ticks. He is setting up numerous experimental stations in several states to test this new method. If it works as planned, Carroll hopes to make this technology available to authorities in regions where Lyme disease is a serious problem.
In response to a recent Researching Maintenance piece, Tom Fasulo, a University of Florida entomologist, wrote Grounds Maintenance to suggest some additional internet sites you can access to obtain MSDSs. One is Cornell University's database, which contains over 325,000 MSDSs. This site's address is: http://msds.pdc.cornell.edu/issearch/msdssrch.htm. It lets you search for the desired MSDSs and is very user-friendly. Another useful site for MSDSs is http://ilpi.com/msds/index/chmtl, the site of Interactive Learning Paradigms Inc. It provides excellent information about MSDSs as well as numerous links to related sites. Fasulo also notes that the University of Florida's Institute of Food and Agricultural Science website, at http://www.ifas.ufl.edu/~schoolipm/, has links to both of these sites and many others, as well as information of interest to all pesticide users.
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