Zucchini troubles and questions

Asked July 26, 2020, 12:55 PM EDT

This is my 1st year growing zucchini, ( trying to...) I have 2 in containers and 2 in ground. None are really producing, I just got 3 zucchinis so far. And those were hand pollinated. My other veggies are doing geat, tomatoes, herbs, pepper, even eggplants are finally forming.
I have a question about 1 particular plant in a container. The main stem looks much lighter in color than the other plants. Although the leaves seem fine. My question: how would I know if there is vine borer damage? Or other bug damage? IF not bug damage, what else could be causing lack of zucchinis in my plants? ( No fun to hear " zucchinis easy to grow and produce a lot" from my friends !)
FYI, the 3rd photo attached, is from the plant in question, I thought Id get 1 Zuch but went bad, as you can see. Can u see if its mold?
Thanks for your help!!

Montgomery County Maryland

1 Response

There may be several reasons for lack of fruits. Zucchini can be difficult to grow in a container. It will be difficult to get many fruits unless the container is about 15-20 gallons. You may be dealing with lack of space, moisture, fertilization, etc. Here is our page on container growing, soil types, watering, etc.

You may also be dealing with pollination and heat stress issues. Poor pollination and fertilization of ovules; could also be heat-related in that high temps can interfere with pollination/fertilization (can degrade/kill pollen and damage reproductive organs).

Summer squashes requires cross-pollination -- pollinating insects must move pollen from male to female flowers multiple times before a full-size fruit will form. Most of the first flowers are male flowers and when female flowers do appear (they can be identified by the small, undeveloped fruit below the flower) they may drop off. Small fruits may also dry up and drop off. This is caused by incomplete flower pollination or fertilization of the tiny undeveloped seeds (ovules), caused by low pollinator activity or heat stress. If the plants are otherwise healthy, you will start to see more fruits as the season progresses. Here is our page on squash https://extension.umd.edu/hgic/topics/summer-squash

We are not seeing evidence of squash vine borer. Here is what it looks like https://extension.umd.edu/hgic/topics/squash-vine-borer-vegetables

The fruit in the photo is infected with Choanephora fruit rot. This is common during warm, humid, wet weather. The pathogen attacks the flowers and then moves into the fruits. Simply remove flowers once the fruits start to grow (after pollination and fertilization of ovules). Remove affected fruits. Pruning out excessive inside foliage can help with the problem.