Treatment threshold recommendations for greenbug in sorghum within the southern Great Plains (from Wright et al. 2006, Cronholm et al. 2007, Michaud et al. 2014, Royer 2015)
| Plant stage . | When to treat . | ||
|---|---|---|---|
| 0–1-leaf stage | Kansas thresholds | Nebraska thresholds | Arkansas, Oklahoma, Texas thresholds |
| 25–50 greenbugs/plant. Colonies or numerous winged adults present on majority of plants. Risky to wait until visible damage is obvious. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. | |
| 3-leaf stage | 50–100 greenbugs/plant. As above, before general signs of stress are visible. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. |
| 5-leaf stage | 150–300 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies of greenbugs and initial signs of reddening appear. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Mid-whorl stage | 300–600 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies, but before leaves begin to die. | Treat if greenbug colonies are beginning to cause red or yellow leafspotting on lower leaves of most plants AND parasite numbers are less than 20% of greenbugs parasitized. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Boot | 700–1,000 greenbugs/plant Some lower leaves wet and sticky with honeydew. Some leaves yellowing/reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of one functional leaf. |
| Heading through soft dough | 700–1000 greenbugs/plant. Some lower leaves wet and sticky with honeydew. Some leaves yellowing and reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of two functional leaves. |
| Plant stage . | When to treat . | ||
|---|---|---|---|
| 0–1-leaf stage | Kansas thresholds | Nebraska thresholds | Arkansas, Oklahoma, Texas thresholds |
| 25–50 greenbugs/plant. Colonies or numerous winged adults present on majority of plants. Risky to wait until visible damage is obvious. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. | |
| 3-leaf stage | 50–100 greenbugs/plant. As above, before general signs of stress are visible. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. |
| 5-leaf stage | 150–300 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies of greenbugs and initial signs of reddening appear. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Mid-whorl stage | 300–600 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies, but before leaves begin to die. | Treat if greenbug colonies are beginning to cause red or yellow leafspotting on lower leaves of most plants AND parasite numbers are less than 20% of greenbugs parasitized. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Boot | 700–1,000 greenbugs/plant Some lower leaves wet and sticky with honeydew. Some leaves yellowing/reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of one functional leaf. |
| Heading through soft dough | 700–1000 greenbugs/plant. Some lower leaves wet and sticky with honeydew. Some leaves yellowing and reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of two functional leaves. |
Treatment threshold recommendations for greenbug in sorghum within the southern Great Plains (from Wright et al. 2006, Cronholm et al. 2007, Michaud et al. 2014, Royer 2015)
| Plant stage . | When to treat . | ||
|---|---|---|---|
| 0–1-leaf stage | Kansas thresholds | Nebraska thresholds | Arkansas, Oklahoma, Texas thresholds |
| 25–50 greenbugs/plant. Colonies or numerous winged adults present on majority of plants. Risky to wait until visible damage is obvious. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. | |
| 3-leaf stage | 50–100 greenbugs/plant. As above, before general signs of stress are visible. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. |
| 5-leaf stage | 150–300 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies of greenbugs and initial signs of reddening appear. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Mid-whorl stage | 300–600 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies, but before leaves begin to die. | Treat if greenbug colonies are beginning to cause red or yellow leafspotting on lower leaves of most plants AND parasite numbers are less than 20% of greenbugs parasitized. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Boot | 700–1,000 greenbugs/plant Some lower leaves wet and sticky with honeydew. Some leaves yellowing/reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of one functional leaf. |
| Heading through soft dough | 700–1000 greenbugs/plant. Some lower leaves wet and sticky with honeydew. Some leaves yellowing and reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of two functional leaves. |
| Plant stage . | When to treat . | ||
|---|---|---|---|
| 0–1-leaf stage | Kansas thresholds | Nebraska thresholds | Arkansas, Oklahoma, Texas thresholds |
| 25–50 greenbugs/plant. Colonies or numerous winged adults present on majority of plants. Risky to wait until visible damage is obvious. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. | |
| 3-leaf stage | 50–100 greenbugs/plant. As above, before general signs of stress are visible. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | 20% of leaves visibly damaged. |
| 5-leaf stage | 150–300 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies of greenbugs and initial signs of reddening appear. | Treat if greenbug colonies are present on 10–20% of plants and visibly yellowing or sporting on leaves is present. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Mid-whorl stage | 300–600 greenbugs/plant. Majority of plants are infested with rapidly increasing colonies, but before leaves begin to die. | Treat if greenbug colonies are beginning to cause red or yellow leafspotting on lower leaves of most plants AND parasite numbers are less than 20% of greenbugs parasitized. | Visible damage on leaves (red spots, yellow leaves) but before an entire leaf has been killed on 20% of plants. |
| Boot | 700–1,000 greenbugs/plant Some lower leaves wet and sticky with honeydew. Some leaves yellowing/reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of one functional leaf. |
| Heading through soft dough | 700–1000 greenbugs/plant. Some lower leaves wet and sticky with honeydew. Some leaves yellowing and reddening with occasional leaves dying. Small to large increasing colonies present on the majority of plants. | Treat if greenbug colonies are on most plants, before one lower leaf has been killed AND parasite numbers are less than 20% of greenbugs parasitized. | Death of two functional leaves. |
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