Plant Doctor Kim

08/11/2026

I have recently received several samples of plants suffering from nematode infestations. In the photo from my lab microscope, you can see blue arrows pointing to several plant pathogenic nematodes clustered around a section of bermuda grass root. The nematodes are pending species identification.

07/13/2026

I recently attended a pecan field day, where my colleague, Dr. Jo taught pecan growers about plant diseases to be on the lookout for. It was great seeing him, and my interns learned so much about pecan production.

07/01/2026

Ya'll, this year I am seeing downy mildew popping up in south central & SW Texas. This Mexican petunia is showing signs and symptoms of downy mildew, note the grey "fluff" on the leaves. While I have not observed this to be frequently fatal on Mexican petunia, it can cause damage and reduce plant performance in the flower bed. This problem can be minimized by improving air circulation, reducing leaf wetness, remove and disopose of infected plant material, especially at the end of the season.

06/24/2026

We found Gracie! She decided to join us scouting in a squash field and be my 4th 2026 SCARLET intern, NBD.

06/19/2026

Y'all, with all the rain we've had in SW Texas, I am seeing Phytophthora (pronounced fi-tawf-thor-ah) popping up in fields! This is a very common problem in summer squash and other cucurbits, bell peppers, many other vegetables, ornamental flowers, and even sesame! Phytophthora diseases cause water-soaked (wet-looking) plant tissues and often collapse of the plant. Fruits can also be infected and a total loss. Planting disease-resistant varieties is the "front-line" defense though improving drainage, applying appropriate (labelled) fungicides, and disposing of infected plant material can help combat the problem.

06/15/2026

In keeping with my last tomato post, check out this tomato leaf. The hole circled in blue is due to flea beetle damage (flea beetles love nightshade crops like tomato, pepper, eggplant). The leaf spot circled in gold is Septoria leaf spot, which is unfortunately common on tomato.
Much like with early blight, to control Septoria leaf spot, focus on removing infected leaves, improve air flow, use fungicides, and practice crop rotation season to season.
To manage flea beetles, use of various insecticides, diatomacious earth, and row covers can help reduce flea beetle impacts on the crop.

06/13/2026

Early blight is a common problem on tomato and other nightshade crops. The disease is caused by a fungus in the genus (group) Alternaria (species include Alternaria solani and Alternaria linariae, also known as A. tomatophilai).
Management efforts for home production should focus on: 1. remove infected plant material; 2. cultural control with efforts focused on avoiding getting leaves wet when watering, improving air flow with pruning, and mulching the soil to reduce water splashing up onto the leaves; 3. fungicide sprays, and 4. crop rotation to unrelated (non-nightshade) crops.

06/11/2026

Y'all, this elm leaf is showing symptoms of bacterial leaf spot. Note how spots are limited in their expansion by the leaf veins. This is a classic indicator of bacterial leaf spot.

05/29/2026

Blossom end rot ya'll....

05/29/2026