Tobacco Insect Scouting Report. June 20, 2014

— Written By tcmclamb and last updated by
Tobacco plants in Greene County. Photo: Hannah Burrack

Tobacco plants in Greene County. Photo: Hannah Burrack

In our eight week of scouting, we exceeded threshold for one of the key tobacco pests for the first time! Our Eastern 1 (Grower Standard) and Eastern 2 (IPM) fields were both over threshold for tobacco budworms. The grower standard field (Eastern 1) was treated with an application of Besiege (containing chlorantraniliprole and lambda-cyhalothrin) about a month ago when no budworm larvae were present. Budworm counts in both fields were exactly the same, suggesting that this preventative treatment had no measurable effect on tobacco budworm infestation, which we would expect since the plants have grown considerably in one month.

Tobacco budworm pressure was also high at our research station locations, and several of our plots were treated either for threshold comparison or to assess the efficacy of registered and unregistered insecticides.

While we only saw one stink bug in our scouting locations this week, we observed several brown stink bugs on tobacco in a field in Greene County. Stink bugs cause characteristic leaf wilting when they feed on the mid rib of tobacco leaves. Normally leaves can bounce back from this injury unless the weather is hot and dry (sound familiar?). In the case of hot dry weather, leaves may experience some sun scald, but the damage is generally not significant enough to justify treatment. We do not have thresholds for stink bug treatment in tobacco for this reason.

Interestingly, no tomato spotted wilt virus was observed in any of the grower fields this week despite the high numbers of thrips that we observed this early summer. This supports our assumption that while thrips numbers may have been high this year, they may have been uninfected and not transmitting large amounts of virus or the plants may have been large enough to withstand a systemic infection.

Scouting Report, Eastern 1 – Grower Standard Field

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infested plants Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No treatment  0 beetles/plant – No treatment 12% tobacco budworm budworm infested plants – Treatment recommended 0 – No treatment 0 – No treatment None observed

Scouting Report, Eastern 2 – IPM Field

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm  infested plants Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No Treatment 0 beetles/plant – No treatment 12% tobacco budworm infested plants – Treatment recommended 0 hornworms/plant – No treatment 0 – No Treatment None observed

Scouting Report , Eastern 3 – Grower Standard Field

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infested plants Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No treatment  0 beetles/plant – No treatment 0% tobacco budworm budworm infested plants – No treatment 0 – No treatment 0 – No treatment 6.1 thrips per plant, 0.025 stink bugs per plant

Scouting Report, Eastern 4 – IPM Field

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm  infested plants Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No Treatment 0 beetles/plant – No treatment 2.5% tobacco budworm infested plants – No treatment 0 hornworms/plant – No treatment 0 – No Treatment 3 thrips/plant

Scouting Report Piedmont 1 – Grower Standard Field

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infested plants Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No treatment  0.05 beetles/plant – No treatment 2.5% tobacco budworm budworm infested plants – No treatment 0 – No treatment 0 – No treatment 1.03 thrips/plant, 0.025 Japanese beetles/plant

Scouting Report, Piedmont 2 – IPM Field

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm  infested plants Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No Treatment 0.08 beetles/plant – No treatment 4% tobacco budworm infested plants – No treatment 0.02 hornworms/plant – No treatment 0 – No Treatment 0.6 thrips/plant

Here are the scouting reports from the control plots for our experiments at the Upper Coastal Plain Research Station near Rocky Mount, NC and the Lower Coastal Plain Research Station near Kinston, NC. For some of these experiments, the control plots receive no insecticide treatments for the entire season. For some of the experiments, we are interested in only caterpillar pests so all plants in the experiment, including the control plots, are treated in the greenhouse with imidacloprid to prevent other early season pests.

On Station, Kinston – Control plants with no insecticide treatment

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infestation Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 1% aphid infested plants – No Treatment 0 beetles/plant – No treatment 62% budworm infested plants – No treatment** 0 – No treatment 0 – No Treatment 3% of plants infected with Tomato spotted wilt virus

On Station, Kinston – Control plants treated with imidacloprid

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infestation Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No Treatment 0 beetles/plant – No treatment 68% budworm infested plants – No treatment** 0 – No treatment 0 – No Treatment 5% of plants infected with TSWV

On Station, Rocky Mount – Control plants with no insecticide treatment

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infestation Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No Treatment 0 beetles/plant – No treatment 0 – No treatment 1% Hornworm infested plants – No treatment 0 – No Treatment 0 – No treatment

On Station, Rocky Mount – Control plants treated with imidacloprid

Insect observation No. aphid infested plants Flea beetles/plant Percent tobacco budworm infestation Hornworms/plant Percent cutworm damaged plants Other insects
Treatment needed? 0 – No Treatment 0 – No treatment 2% budworm infested plants – No treatment 0 – No treatment 0 – No Treatment 1% of plants infected with TSWV – No treatment

** Plots were not treated due to the experiment, but some plots with similar amounts of budworm infestation, were treated. 

More information

Stink bugsTobacco Growers Information

See last week’s scouting report.