Yellow Wood Sorrel Seed, Vol. 5, No. 30

Oxalis stricta

Those aren’t bugs, they’re seed! Because of their size, shape and segmented appearance, wood sorrel seed are often mistaken for scale insects, mealybugs or some type of immature insect.  These things can fool experienced nurserymen, gardeners and professional entomologists, at least initially.   The first sample I ever received of these was submitted years ago by an experienced nurseryman who was concerned he had some type of new insect pest on his greenhouse plants.  At first glance I also thought this must be some type of insect pest I had never seen before.  Only after I put them under the microscope and began looking for legs and heads and found that the things could not be easily punctured with a teasing needle did I realize they were seed.  But what kind of seed, and why was this nurseryman suddenly finding them on potted plants in his greenhouse?
 
Yellow wood sorrel and other types of oxalis sometimes grow as weeds in potted plants in nurseries and greenhouses.  When the small, okra-like seed pods mature they burst explosively, throwing the tiny seed up to 10 or 12 feet. Impatiens, aka touch-me-nots, exhibit a similar seed dispersal habit.  In this case, the nurseryman was growing various potted plants on the benches in his greenhouse, but he also had a row of hanging baskets over the walkways between the benches, and these hanging baskets had a light infestation of wood sorrel growing as weeds in the baskets.  When the wood sorrel matured and began throwing seed, the nurseryman began to notice this mysterious infestation on the plants growing below.  This is not a unique situation; many other greenhouse producers have observed similar events over the years.

Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service. The information given here is for educational purposes only. Always read and follow current label directions. Specific commercial products are mentioned as examples only and reference to specific products or trade names is made with the understanding that no discrimination is intended to other products that may also be suitable and appropriately labeled. 

Mississippi State University is an equal opportunity institution.

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