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%.
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. 
Fig. 1. Mozena obtusa adult and nymphs
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.
