Update on the Mozena leaf-footed bug in Texas High Plains cotton

 Suhas Vyavhare and Kerry Siders

Leaf-footed bug, Mozena obtusa (fig. 1) is being spotted on a variety of plants across the Texas High Plains. We have gotten a few inquiries about how damaging this insect is to cotton and what insecticides would be most effective. In cotton, we have spotted this insect in multiple counties across the South Plains region. The numbers remain very low in all the fields where we have seen it except one field in Hockley County where it was found to infest cotton in large numbers (15-20 immatures/plant). In this particular field, insects appeared to be moving from the adjacent fallow field with mesquite trees which are preferred host of Mozena bug. Even the immature stages of this insect are quite agile and can travel some distance in search of new hosts. Fig. 2 shows results from the insecticide efficacy trial being conducted near Sundown, TX. Data collected at 3 and 7 days after treatment application indicate pyrethroids to be the most effective insecticides. We are also collecting data on the impact of Mozena bug on square retention in cotton. Thus far, we have not observed any square loss that can be attributed to this insect. Overall, square retention across the trial area remains over 90%.

Fig. 1. Mozena obtusa adult and nymphs

We are beginning to notice a few egg masses and small immatures on cotton plant indicating its suitability as a host for Mozena bug. With the absence and/or reduction in the availability of preferred hosts such as mesquite and other legumes, this leaf-footed bug can become an issue in cotton. Leaf-footed bugs in general prefer to feed on fruits and seeds and therefore their populations need to be monitored closely as our crop enters the boll development phase.  I would treat them more like stink bugs which feed in the similar manner with their piercing and sucking mouth parts and are mainly boll feeders in cotton. When scouting fields monitor both insect population density and the extent of damage to the crop (fruit retention, external and internal boll injury) and base the treatment decisions accordingly.

Here is a link to our recently updated cotton insect management guide: https://lubbock.tamu.edu/files/2022/07/managing-cotton-insects-in-texas.pdf

  

Fig. 2. Insecticide efficacy against leaf-footed bug, Mozena obtusa in Texas South Plains cotton. Means showing the same letter are not significantly different [Tukey’s HSD; P = 0.4226 (3 days after treatment (DAT)); 0.0302 (7 DAT)].

*Insecticide products were evaluated for research purpose only. When using an insecticide read and follow label directions for safety precautions, rates and preharvest intervals.