Responses of Shade Trees to Pollution

Peterson, G.W. and J.D. Olta. 1979. Controlling phomopsis blight of junipers. Am. Nurseryman 149(5): 15, 75, 78, 80-82. Phomopsis blight (cedar blight) is common in the Great Plains from South Dakota to Texas and eastward to the Atlantic coast. Losses have been especially severe in seedling beds of Juniperus virginiana and J. scopulorum. Phomopsis initially infects foliage, then spreads to and kills stem tissues. Damage from drought can be confused with Phomopsis blight. In both cases, tips of branches may be killed. Fungicides are needed for effective control in seedling beds. Removing infected seedlings from beds (roguing) can reduce the amount of infection. Poorly drained areas should be avoided because losses are often greater where water tends to stand. Some nurseries have abandoned production of highly susceptible cultivars. Phomopsis can cause unsightly junipers in landscapes but seldom kills established trees. Shurtleff, Malcolm. 1978. The myth of pesticide-induced injuries. Grounds Maintenance 13(9): 1. There are many myths that need to see the light of day. In the 16-year period from 1960 to 1 975, there were 35 deaths in Illinois caused by accidental ingestion of pesticides. Interestingly, only one death resulted from a pesticide used for an agricultural purpose. The remaining 34 deaths resulted from household pesticides. Sixteen casualties were the result of improper pesticide storage; 15 deaths occurred while the pesticide was in use. Even more startling is that 1 9 of the victims were three years old or younger. Seventy-four percent of the deaths were children 1 2 years of age or younger. Sodium arsenite, a weed killer, was involved in more accidental deaths (8) than any other pesticide, with sodium fluoride (6) and phosphorus paste baits (5) in second and third places. Several deaths occurred because sodium arsenite was poured into pop bottles and stored in refrigerators. There have been no deaths reported in Illinois from accidental exposure or ingestion of pesticides since 1973. The facts should explode some myths fostered by the mass media. The data point out where pesticide accidents occur and how. Hopefully, we can learn from past mistakes and can concentrate now on correcting the deficiencies that allow accidental poisonings to occur. Smith, Ronald C. 1978. Tree staking and guying. Grounds Maintenance 13(9): 50, 52. There are variations in staking methods. These and the standard staking methods are discussed, plus data on what research shows goes on with staked and unstaked trees. The need for tree staking arises from the desire to keep trees in their upright position until their root systems penetrate the soil to provide sufficient anchorage against high winds. Not all trees require staking. If the ball size is up to par, the top properly thinned at planting and the backfill is according to specifications, many larger deciduous, nurserygrown trees will flex but not lean under normal prevailing wind and rain conditions. Any wild or native-grown trees should be staked. This is because the root systems of such trees are shallow and have had a significant portion of their surface area removed from transplanting. The staking should remain for no more than two years, with frequent checks on the wires to be sure no girdling takes place.