-3- 



These crawlers can be controlled by a thorough application of a spray containing 

 malathion or diazinon. If malathion is used, mix two teaspoons of 50- to 57- 

 percent liquid concentrate in each gallon of spray. Diazinon should be mixed, 

 using 2 teaspoons of the 25-percent liquid concentrate per gallon of spray. 



Pine sawf lies . 



in the southern section of 



They are hatching and beginning to feed on the needles of pine 

 trees in the southern section of the state. These black-headed, grayish-green 

 caterpillars strip the needles from the red, white, jack, and other pine spe- 

 cies. Christmas tree plantings, as well as other pine plantings, should be 

 observed at regular intervals during the next three weeks for this insect. 

 Spraying with carbaryl (Sevin) will provide control. 



weeds 



TOXICITY AND THE LABEL 



Most pesticide labels do not directly state the oral or dermal toxicity of the ma- 

 terial, but certain key words on the label indicate the relative toxicity. Toxicity 

 is the inherent capacity of a substance to cause injury or death. 



The words "DANGER" or "POISON" and the skull-and-crossbones symbol are required on 

 the label if the material is highly toxic (see table below). The word "WARNING" 

 is required for moderately toxic materials. "CAUTION" is required for slightly 

 toxic materials. All labels must bear the statement "Keep out of the reach of 

 children." 



Toxicity Classes 



Route 



Term 



Oral LD50 



Dermal LD50 



Probable lethal 

 oral dose for man 



Highly toxic 0-50 0-200 1 tablespoon to 1 teaspoon 



Moderately toxic 50-500 200-1,000 1 teaspoon to 2 tablespoons 



Slightly toxic 500-5,000 1,000-2,000 2 teaspoons to 1 pint 



Practically non-toxic. .5,000-15,000 2,000-20,000 1 pint to 1 quart 



Relatively harmless. . . .more than more than more than 1 quart 



15,000 20,000 



Remember toxicity is only one factor to consider when using pesticides. Always 

 read and heed the label. 



PLANT DISEASES 



SOUTHERN CORN LEAF BLIGHT 



None of the corn- seedling samples received so far at the Plant Disease Clinic 

 have been infected with the southern corn leaf blight (SCLB) . Most problems were 

 caused by (1) cold damage- -frost and low temperatures; (2) mechanical injury- - 

 wind and soil particle abrasion; (3) common seedling blights, such as Diplodia 

 and Gibberella; or (4) some flea beetle activity. 



SCLB infection symptoms on susceptible corn seedlings will appear first as 

 scattered, tiny, circular spots. These will usually have tan centers and a 



