Rutgers Cooperative Extension
Kris Holmstrom, Vegetable IPM Program Associate,
Rutgers NJAES
Sampling Method: 10 samples per field, random area. Sample 5 consecutive plants for a total of 50 plants.
Heading type: Broccoli, Cabbage, and Cauliflower
Notes – check for:
- Look at upper and lower leaf surface of any leaf showing caterpillar-feeding injury. Check the innermost leaves for the presence of caterpillars.
- Observe the presence or absence of flea beetles from an upright position so as not to disturb these pests.
- Inspect the overall plant for wilting (possible maggot infestation), the presence of aphids, pale blotches on leaves (harlequin bug feeding), alternaria and bacterial diseases.
- Check the lower leaf surface for the presence of downy mildew sporulation of any leaf having yellow lesions on the upper surface.
Stage: 0-4 true leaves
| PEST | THRESHOLD |
| Flea beetle | Flea beetles present, damage on >/= 50% of plants |
| Caterpillar pests | >/= 10% of plants infested |
| Harlequin bugs | >/= 5% of plants infested |
| Cabbage aphids | >/= 10% of plants infested |
| All diseases | Presence |
Stage: 4 leaves – head fill
| PEST | THRESHOLD |
| Flea beetle | >/= 50% plants with flea beetles |
| Caterpillar pests | >/= 20% plants infested |
| Harlequin bugs | >/= 10% of plants infested |
| Cabbage aphids | >/= 10% of plants infested |
| All diseases | Presence |
Stage: mature head
| PEST | THRESHOLD |
| Flea beetle | >/= 50% of plants |
| Caterpillar pests | >/= 5% of plants infested |
| Harlequin bugs | >/= 5% of plants infested |
| Cabbage aphids | >/= 5% of plants infested |
| All diseases | Presence |
Leafy type: Brussels sprouts, Collards, and Kale
Notes – check for:
- Look at upper and lower leaf surface of any leaf showing caterpillar-feeding injury. Check the innermost leaves for the presence of caterpillars.
- Observe the presence or absence of flea beetles from an upright position so as not to disturb these pests.
- Inspect the overall plant for wilting (possible maggot infestation), the presence of aphids, pale blotches on leaves (harlequin bug feeding), alternaria and bacterial diseases.
- Be sure to check several sprouts as they develop on the side of Brussels sprout stalks for these as well.
- Check the lower leaf surface for the presence of downy mildew sporulation of any leaf having yellow lesions on the upper surface.
Stage: 0-4 true leaves
| PEST | THRESHOLD |
| Flea beetle | Flea beetles present, damage on >/= 50% of plants |
| Caterpillar pests | >/= 10% of plants infested |
| All diseases | Presence |
Stage: 4 leaves to harvest
| PEST | THRESHOLD |
| Flea beetle | >/= 50% plants with flea beetles |
| Caterpillar pests | >/= 20% plants infested |
| All diseases | Presence |
