June 24, 2009
I am beginning to feel that I could write one column and use it for the last 3 weeks! Rain and all of the associated garden problems continue unabated.
One of the biggest garden problems this week continues to be aphids on all sorts of plants. I think that the reason aphids are such a problem is that the weather being cool and damp makes for ideal breeding conditions. Add in the fact that most of the predators of aphids aren’t active in this kind of weather has made it easy for aphid problems to skyrocket.
Generally speaking, aphids should be easy to control. An application of a pyrethrum spray should knock back the population. If you follow up with another application in 4 days, you usually disrupt the lifecycle and eliminate most of the population. However, the rain has made it almost impossible for a 2-application spray schedule to effectively work. You spray the plants and the rain washes it off before it has time to work. The insecticides may kill on contact, but you hope for a bit of residual action to help keep the population of aphids in check. This is not to say to not spray your plants until the rain and showers stop. If you do, there will continue to be major damage on your plants.
Slugs also love this kind of weather. We have seen so many leaf samples with the tell tale smooth edged holes that indicate that slugs are feeding on plants. If you keep up with the application of an iron phosphate slug control, you will eventually knock back the slug population. It is kind of interesting to note that we have started to get reports of snails feeding during the day on plants. For years, snails were a fairly rare occurrence this far north. This just goes to show how well garden pests can adapt to our climate.
Long stretches of rainy and cool weather are also prime times for fungus diseases to hit all our garden plants. The problem is, again, that it is difficult to effectively spray plants with a fungicide and have time for it to work before the rain washes it off the plants. Bayer has a combination fertilizer, systemic insect control and systemic fungicide that will work well on rose bushes and other ornamental plants. Unfortunately, you cannot use it on your vegetable plants. Again, you will just have to do multiple applications of fungicide to your vegetable plants to try and check the spread of fungus diseases. Many of your perennials will be subject to fungus diseases. It is important to check your perennials too when you make your applications of fungicide.
The other unfortunate occurrence is that all of the rain and cool conditions has caused plants to just rot away. Cucumbers and members of the squash family have been hard hit by conditions that cause plants to rot. Heat loving annual such as zinnias, New Guinea impatiens, and portulaca have been hit especially hard. All we can hope for is the projected end of this rainy weather and then you will be able to re-plant and we can get on with the gardening season.
Well, that’s all for this week. I’ll talk to you again next week.