| MINIMUM FOR | MINIMUM FOR | OPTIMUM FOR |
  | INFECTION | REPRODUCTION | ACTIVITY |
ROOT KNOT |   |   |   |
MELOIDOGYNE SP. |   |   |   |
M. CHITWOODI | 45F | 45F | 68-77F |
(COLUMBIA) | (6C) | (6C) | (20-25C) |
M. HAPLA | 54F | 54F | 77-86F |
(NORTHERN) | (12C) | (12C) | (25-30C) |
M. INCOGNITA | 65F | 50F | 76-90F |
(SOUTHERN) | (18C) | (10C) | (25-32C) |
  |   |   |   |
SUGARBEET CYST |   |   |   |
HETERODERA | 50F | 46F | 70-81F |
SCHACHTII | (10C) | (8C) | (21-27C) |
  |   |   |   |
NEEDLE |   |   |   |
LONGIDORUS AFRICANUS | DAMAGE TO LETTUCE SEEDLINGS IS MINIMAL AT SOILTEMPERATURES LESS THAN 22C (72F) |   |   |
This table summarizes information available in the literature on the minimum levels at which nematodes are able to infect a plant.
If planting is to take place at a time of year when temperatures are below this infection minimum, or when soils are cooler, less damage can be expected than when soil temperatures are optimum.