| MONTH | IMPERIAL COUNTY | SANTA BARBARA COUNTY | SAN JOAQUIN COUNTY | |
| JANUARY | 111 | 51 | 36 | |
| FEBRUARY | 140 | 68 | 72 | |
| MARCH | 247 | 109 | 149 | |
| APRIL | 320 | 141 | 199 | |
| MAY | 423 | 223 | 298 | |
| JUNE | 518 | 273 | 360 | |
| JULY | 580 | 316 | 417 | |
| AUGUST | 620 | 333 | 377 | |
| SEPTEMBER | 547 | 254 | 269 | |
| OCTOBER | 401 | 191 | 237 | |
| NOVEMBER | 188 | 93 | 96 | |
| DECEMBER | 85 | 14 | 8 | |
| TOTAL | 4180 | 2066 | 2518 | |
| SEPT-APR | 2039 |
The predominant host crop in Imperial county (southern California) and San Joaquin county (just south of Sacramento) is sugarbeet. Although in past years, sugarbeets were grown in Santa Barbara county (a coastal area), cole crops are currently a much more profitable crop.
The variability in nematode degree days both between counties and at different times of the year in the same county is evident. In some months, nematodes may go through more than a generation in a single month. At other times of the year, several months will be required to complete a generation.
In California, sugarbeet processing plants do not operate all year round. They typically operate during the period of time that sugarbeets are being harvested.
In San Joaquin County, for example, winter rains prevent fields from being harvested for several months. Sugarbeets also grow more slowly during the winter, so that fall planted beets are not ready to harvest in early spring. It is common practice to overwinter some sugarbeet fields planted the previous year in order for processing plants to begin earlier in the spring. Sufficient nematode degree days accumulate during this overwintering period for an additional generation of nematodes. This increased population, can result in the need for a significantly longer period of nonhost rotation.
Research conducted in the Imperial Valley indicates how the number of days required for sugarbeet cyst nematode to go through a generation decreases during the warmer months of the year.