In a normal year, our Texas High Plains cotton can be infested by thrips, plant bugs and caterpillar pests. Among these, a complex of several thrips species is the primary and most common pest for the majority of the cotton acreage in the region.
In a post-Temik era, insecticide seed treatments are the tools of choice for thrips management. In addition to insecticide seed treatments, a foliar application of acephate (Orthene) is a good option for thrips control.
The use of foliar insecticide applications may require additional field scouting labor in order to properly follow recommended action thresholds. In a study conducted last year, we found that either the use of a seed treatment or a one-time application of Ortheneor Vydatecould result in a 5-10% yield gain over plots not receiving treatments of any type.
If you are growing cotton in areas with a persistent thrips history, using insecticide seed treatments is suggested. Our research studies have found that Aerisand Avicta Complete for cotton are both equally effective seed treatment packages for thrips in High Plains growing conditions.
In addition to insecticidal seed treatments, there are other considerations related to effective thrips management in cotton. Maintaining good plant health is important in order for small cotton seedlings to sustain injury by thrips.
3 healthy plant points to consider:
- Use quality seeds with good seedling vigor and timely germination.
- Plant seeds into seed beds that contain adequate moisture and soil temperatures are within an optimum range.
- If possible, plant seeds in fields managed under a reduced tillage system, such as terminated wheat stubble, so that the young seedlings do not suffer significant wind injury due to blowing sand. Of course, in many cases, the lack of rainfall and limited irrigation capacity do not allow for the establishment of a cover crop.
If seeds are planted when soil temperature is below optimum, it takes longer for seeds to germinate and grow. In this situation, the value of an insecticide seed treatment may be compromised and additional foliar applications might be required if consistent thrips pressure persists in the field.
An ideal situation to plant cotton seeds is when soil temperature is above 60-62º F (at an 8-inch depth) with a forecast for open weather for at least one week. For thrips management, the bottom-line is to get the plant established and growing quickly so that plants can escape or quickly “grow through” the susceptible period of thrips injury, i.e., fourth true-leaf stage.
Windy conditions can also affect seedling growth. Sand particles blowing with high velocity winds can injure leaf tissues, especially when seedlings are young and the weather conditions are very dry. In recent years, dry windy conditions accompanied with blowing sand have been very prevalent during the planting and stand establishment period for much of the High Plains cotton acres. Cotton planted with some cover such as residual wheat stubble provide good protection from the winds and sand as evident in the picture in this article. Weak, slow growing seedlings are more vulnerable to thrips injury, resulting in the plants requiring more time to recover and these growth delays may subject the plants to other stresses such as diseases and nematodes.