Answer to Virág's question re: diseases

On 15 March Virág asked the following quesiton:

Hy! What kind of diseases have you had in your garden? And what have you done against them?

I have taken the liberty of posting my answer here for all to see.

wb

Hello  Virág:

The biggest problem disease we have is septoria (septoria lycopersici) leaf spot in our tomato plants.  

This fungus is endemic in the soil of our garden and we control it by a number of methods. Culturally we rotate plantings and keep them open and uncrowded. For example, last year we planted five plants in an 8 m long row and used a ‘Florida weave’ trellis method. 

We do not water at night or in the early morning – this helps keep the leaves dry. We also try to water near the ground, using a ‘leaky hose’ technique or spot hand watering. If the weather cooperates we don’t have to water at all, but it is necessary from time to time.
We also prune heavily, especially near the ground, an tie up sagging fruiting branches.  

If possible we plant ‘septoria resistant’ cultivars but not all of our favorite tomato types are available in this form.  

Since the spores come from the soil, we cover the soil around the plantings with straw mulch. This keeps mud from getting splashed up onto the leaves in heavy rains and keeps sagging branches from coming in direct contact with the soil.  

The only chemical we use is copper-octanoate in a soap solution. I spray the plants weekly, starting with the initial outdoor planting until mid August.  

This combination of measures has given us reasonable control of septoria during the past few seasons.  

In earlier seasons we have lost significant production to septoria (in 2003, I think, we lost nearly the entire crop – after that we started dealing with it aggressively). The last year I can recall much infection was 2005 but constant vigilance is the price of freedom (from septoria as well). If you look carefully at the 2005 Garden photo sequence, especially the ‘W&W 2005 Garden Southeast Views’ set, images 11, 12 and 13, you will see the progress of black, wilted leaves in the tomato plants located in the third row from the west end. The plants bore fruit – you can see the fruit exposed as the leaves wilt – but the fruit was not in peak condition. As you can see, other plantings in that year were not as severely affected. These were ‘septoria resistant’ cultivars and were on an outer row (the location helped them dry more quickly after rain and watering, too). That year I did not spray the copper octanoate solution until the septoria was well established and by then it was too late to achieve good control.

We have had other diseases at times but none of them compare with septoria in severity. There is a mysterious wilt that sometimes affects our basil plantings – it can kill a plant in a week or two. It, too, is a fungus, possibly related to septoria, but I haven’t researched it thoroughly. My control measure is to plant plenty of basil and remove affected plants as soon as possible.

Corn (maize) is affected by a very strange disease that the local farmers call ‘smut.’ The disease converts the seeds to fungus-like structures that are filled with black spores that scatter like dust when the dry ear is opened. See corn smut.

We no longer grow corn, not because of smut but because it takes up a lot of space and the production is spotty – it is easier to buy excellent (heavenly!) corn from roadside stands when it is in season. Last year we substituted sunflowers for our corn crop – a pretty field but the 10 kg of sunflower seeds we harvested weren’t worth the trouble.

This year we plan to work the former cornfield into an area suitable for planting raspberry and blackberry plants, which will go in either in the fall of 2009 or the spring of 2010. Farmers have to think for the long term!

This is a very long answer to a simple question.   I hope it's not boring.

Have fun,

Warren Buckles