By: Ed Bynum, Pat Porter, Blayne Reed, Kerry Siders, and Tommy Doederlein
Timing effective treatment to control sugarcane aphids (SCA) in sorghum depends on the size of the SCA population. Follow these guidelines to make treatment decisions.
First Detection: Is the Field at Risk?
- Once a week, walk 25 feet into the field and examine plants along 50 feet of row. Check at least 4 locations per field (total 60–80 plants).
- Inspect underside of leaves from upper and lower canopy from 15–20 plants per location.
- If honeydew is present, look for SCA on the underside of a leaf above the honeydew.
- Sample each side of the field and sites near johnsongrass and tall mutant plants.
- If no SCA are present, or only a few individual wingless/ winged aphids are on upper leaves, continue once-a- week scouting.
- If SCA are found on lower or mid-canopy leaves, begin twice-a-week scouting. Use the Grain Sorghum Action Threshold (over) to determine if the infestation is at or exceeds the action threshold.
Control Options after First Application
- Check fields for control after 4–7 days.
- If poor control and aphid colonies of 50 or more per leaf are still present, repeat application.
- If there was good control of the aphid, continue scouting fields twice a week for re-infestation or a rapid increase in aphid numbers.
- For whorl to early dough growth stages, use the Grain Sorghum Action Threshold for any second applications.
- From dough to late dough growth stages, a second application may be required when aphids are re- establishing, 40%–50% of the total leaf area has aphid damage, and predator populations are not suppressing aphid populations.
- At black layer growth stage through harvest, an application may be required to prevent harvest problems.
Forage Sorghum Management
Treatment thresholds have not been determined for forage sorghums. Until thresholds are available, contact your Extension agent–IPM or Extension entomologist.
Download a printer-friendly version of this publication: Texas High Plains Sugarcane Aphid Management Guide 2016
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