SUMMARY OF INSECT CONDITIONS DURING 1921. 



41 



these months. In May throughout this region the weather suddenly 

 changed, this month showing a deficiency in temperature and an 

 •excess in rainfall. The warm, dry weather of the early spring 

 facilitated seeding and the greater part of the crop was planted 

 early. The continued warm, dry weather interfered with germina- 

 tion and was very favorable for the heavy infestation of the seed 

 pieces by this insect. The cold, wet weather of May started germina- 

 tion and terminated the erstwhile serious infestation of seed-corn 

 maggots. Later plantings were not infested. 



-2.0 



Fig. 22. — Monthly departures from normal temperature (solid black) and rainfall (white) 

 in the region infested by the seed-corn maggot, January to June, inclusive, 1921. (See 

 also Table 10.) 



Figure 22 and Table 10 give data on departures from normal 

 temperature and rainfall in 1921 in the region infested by the seed- 

 corn maggot. 



Table 10. — Monthly departures from normal temperature and rainfall in the re- 

 gion infested by the seed-corn maggot, January to June, inclusive, 1921. 



DEPARTURES (IN DEGREES FAHRENHEIT) FROM NORMAL TEMPERATURE IN 1921. 



January. February. March. 



April. 



May. 



June. 



New England +3. 4 



New York +2. 7 



Pennsylvania +3. 1 



New Jersey +3. 



West Virginia +3. 3 



Maryland and Delaware +3. 1 



Virginia +2. 2 



North Carolina +1.4 



Regional mean +2. 7 



+3.5 

 + 5.4 

 + 5.5 

 +4.4 



+5.0 

 +4.6 

 + 3.2 





+9.4 

 +9.8 

 + 10.8 

 + 10.3 

 + 10.0 

 +11.3 

 + 10.6 

 +8.9 



+5.6 



+7 



+6 



+0 



+4 



+5 



+4 



+2.6 



+ 10.1 



+ 5.4 



+0.8 



+ 1.6 



-.6 



-.2 



-.7 



-1.6 



-2.7 



-2. 8 



+0.0 

 + 1.6 



+ 2.7 

 + 1.8 

 +3.2 



+ 1.8 



+ 1.8 



