I took the photos at the 41° of northern hemisphere in a greenhouse. The farmer said this vegetable plants are geting always smaler.
I found no comareable material of the disease.
Do you have explainations and how to control this problem?
J HUMER
It is powdery mildew. If you want to control it with chemical fungicide, THIOPHANATE METHYL 2 gm/ liter of water, is best to control it.
#1 looks like powdery mildew.
The grower can reduce humidity, increase air circulation, apply fungicide (Sonata works well for us. Neem oil also seems to inhibit PM.), and/or grow resistant varieties.
We (Hollar Seeds) sell a range of squash varieties with resistance or tolerance to PM.
As far as the plants getting smaller, is the grower rotating his crops or growing squash back-to-back?
Yes, leaf damage looks like powdery mildew; the stem damage might be a stem borer similar to squash stem borer (a lepidopteran moth larva).
It is obviously Powdery mildews. We always manage the problem with soap/ detergent solutions if you don't want to use synthetic chemicals in your garden.
Many thanks for all your useful answers. First I thought also on PM but the stem breakdown seemed to me the more typical symtome. Best regards. JH
There are some commercial non-chemical options available. Look for the potassium bicarbonate products and some of the bacillus products. Some of them can be mixed together and are very effective. Always test a small section first to be sure that it will not harm your crop. Now that you have the disease you will need to maintain a good control program thought the crop cycle and monitor conditions favorable to powdery mildew.
Three pictures, three situations. In the first, powdery mildew, no doubt. The control might be chemical, with a fungicide developed and targeted to this disease in your country, or an alternative product, such as neem, detergent or even milk, which might not be as effetctive, although environmental friendly. The second picture shows a crop which looks fine to me. If the plants are getting smaller (year after year or in the same crop season?), as stated, consider monitoring the fertilization and the environmental conditions. In the third picture, I would not worry if it is a single plant or few plants. However, a close examination will indicate an insect damage or even a crown or root disease that might kill plants. Impossible to say by the picture.
It is obviously Powdery mildews and may be management with eradicate fungicides such as Topas at the earliest signs of the disease. Once mildew growth is extensive, control with any fungicide becomes more difficult.
This disease is Cucurbit Powdery Mildew, it is quit easy to manage, you can identify using the following references, Apply sulfur or copper-based fungicides to prevent infection of susceptible plants.If you need any additional information, I am ready to help you, as my Ph. D. study on this disease
Good luck
Dear Sir Jawad K. Abood Al-Janabi i am Entomologist and my Ph.D is on Cotton Host Plant Resistance Against Jassid and Spotted Boll worm. I Perform my duties in Agriculture Extension. As a Agriculturist i visit field crops and orchards, there is mixed problems on crops. Now i recommended azoxystrobin+difenoconazole 200ml/ac for Powdery and downy mildew, Sir its right or i make mistake please suggest me.
Dear Dr. Fateh Muhammad Kanher
I am so sorry, I missed your question about using azoxystrobin +difenoconazole 200ml/ac against Powdery and downy mildew. In fact, both of them work as fungicides and quite useful for both diseases.
Good luck
- Badges
- Science topic
- Similar topics
- Agricultural Science
- Agronomy