June 26, 2014 Scouting Report
June 26th Tobacco Scouting Report
Generally, most tobacco fields have ample rainfall and rapid growth. Most are approaching or past 50% button stage. Contact suckercides have been applied to about half of the fields scouted with excellent results. These plants have 24-28 leaves, excluding the few small leaves near the button or emerging flower.
In contrast, most growers also have either late planted tobacco or areas with little to no rainfall. Within these areas, plants have approximately 16-20 leaves and are just a bit over about knee high. While these plants may be nearing button stage within the next 7-10 days, few buttons exist now. Thus, these plants are susceptible and attractive to tobacco budworms.
Tobacco Budworms – Tobacco budworms were easily found in all fields ranging from 20-45% plant infestation. Tobacco budworm size ranged from 1/8th -1 inch with most 1/8th inch suggesting newly hatched budworms as the dominant concern. For most fields, insect applications are not warranted since the feeding is concentrated on the button or bloom that is likely to be topped very soon. Too, after button stage, rarely do tobacco budworms cause significant yield loss.
For the remainder of fields, the intensity of tobacco budworms flight may warrant an insecticide treatment. Many of the fields scouted with small plants had concentration as high as 45%. A population this high may cause damage to plants.
Stinkbugs- Stinkbugs rarely reach economic threshold but damage to leaves may be evident. Adult stinkbugs pierce leaves causing leaf wilt. Scouting revealed an occasional green stinkbug but live stinkbugs or evidence of damage was well below 2%.
Tobacco Hornworm – Two tobacco hornworms were found during an entire day of scouting revealing that a few moths are laying eggs. Tobacco hornworms discovered were less than ½ inch long, and technically, should not be counted during scouting. It is mentioned in this post simply to alert scouts to be watchful for this pest within the next weeks.
Miscellaneous Insects – Japanese beetles, grasshoppers and an occasional flea beetle were also present in field. However, seldom do these cause economic damage warranting treatment. The image to the left shows damage by the Japanese beetle. While the individual plant may show great injury, it is simply 3-4 leaves of one plant of about 6000 per acre and is far worse to see than any true economic damage. Lastly, the number of beneficial insects far outnumbered pest (other than the tobacco budworm). Protection of beneficial insects now may provide control of upcoming pest and delay or eliminate the need for an insecticide treatment!
TOPPING AND SUCKER CONTROL
Last weeks comments covered products and timing. This week I’d like to cover a few points regarding management in general. To begin, topping needs to occur as soon as possible. Early topping stimulates root growth making plants more drought tolerant, less prone to lodging, more efficient in nutrient uptake, increases alkaloid production and makes plants less prone to some insects. However, to reap these benefits, topping needs to occurs as early as possible. Waiting until full bloom to top plants reduces yield 20-25 pounds per acre per day!
Secondly, consider plant height when topping. Whenever possible, much of the testing conducted by NCSU aims to harvest 18-22 leaves. Yield in excess of 3,000 lbs/ac is possible and common. Harvest of additional leaves may or may not provide additional weight depending upon climatic conditions of the season. However, additional leaves will indeed require additional labor and curing costs. Given the size of many tobacco producers and that much is done with mechanical harvest equipment, one can’t be too critical of the issue. However, consider that ultimately, one sells tobacco by pounds, not the number of leaves. If excess curing cost, labor or late harvest has been a concern of past production, consider topping plants to harvest 20-22 leaves rather than 24-28 leaves.
Lastly, in last week’s web post, it was mentioned that some chemical topping may occur with timely application of a contact material. This is normal. Regrettably, this season some additional leaf scorch or spots has also been normal. In part, this is likely due to the rapidly growing conditions due to recent rainfall. Too, the hot and humid conditions during the past few days contribute to tender leaves. Contact materials are simply causing very small areas of leaf scorch. Given this situation, it is strongly advised to adhere to the proven production recommendations. Do not add any additional materials to the tank.