Yard and Garden: July 12, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for July 12, 2019. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 2, 2019. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Sarah Browning, Extension Educator in Lancaster County

1. The first question of the show was about ivy growing on a garage. The caller had Japanese beetles earlier this year and sprayed with sevin. Now he is seeing a lot of flying insects, one looks like a lightning bug. What type of insect would this be and will they cause damage to his ivy?

A. They could be lightning bugs which will not harm your plants. Japanese beetles will come back, it would be best to keep spraying to ensure they stay away. You can use the sevin every 10-14 days or you can use a product containing Azadirachtin which has some repellent properties so it will help to keep the Japanese Beetles away longer.

2. A caller has a newly planted maple tree that has brown spots on the leaves. It looks like something is eating it but she can’t find any bugs. The spots look like brown strips with yellow around it. What is causing that?

A. This could be the tree drying up and getting heat stress. This tree was just planted this year so it isn’t established well and will dry out faster in this heat. She has been watering by hand and that isn’t getting the tree enough water. It would be better if she watered with a small sprinkler for about 45 minutes once a week.

3. This caller has a 40-year-old Ponderosa Pine that had diplodia tip blight that got so bad she removed the tree. There is a blue spruce nearby, would that tree be getting the tip blight as well? The spruce has tips of the branches that are bent over and the needles are all bunched together. What would cause that?

A. Diplodia tip blight will not affect spruces. It is a problem for pines, mostly Austrian and Ponderosa. This is not what is affecting the spruce. The damage on the spruce sounds like sirococcus shoot blight. It is past the treatment time for this disease, but it won’t kill your tree in one season. In the spring spruces can be sprayed with chlorothalonil when the shoots are 1/2-2 inches in length and repeated every 3-4 weeks if frequent rains occur.

Blossom end rot on tomato
Blossom end rot on a tomato

4. What can be done for blossom end rot in tomatoes?

A.  Blossom end rot is when the end of your vegetable that is away from the plant rots and turns black. It occurs on the end of the vegetable that had the flower, hence the name blossom end rot. The cause of this disease is a calcium deficiency, but calcium is in the soil in sufficient quantity, uneven watering will reduce the ability of the plant to access this calcium. Calcium has to be dissolved in water for the plant to be able to obtain it from the soil. Adding calcium to your garden is not effective for managing this problem. Not all of your produce should be affected by this problem, they tend to grow out of these conditions later in the summer, so there is no need to treat your garden for blossom end rot. Maintain moisture and mulch to help with this disorder.

5. A caller wants to know what to plant for a fall garden and when it should be planted.

A. Fall gardens can be very beneficial and work better than spring gardens due to the cooler temperatures and higher amounts of moisture in the fall. Start transplants indoors now for things like Brussels sprouts, broccoli, cabbage, and cauliflower. The average first frost date for most of Southeast Nebraska is October 6-16, this comes from data from the High Plains Regional Climate Center. You can use the first frost date to figure out when to plant fall crops. Use the first frost date as a starting point, count backward the number of days to harvest listed on the packet of seeds and add a 10 day fall factor because the plants will mature slower due to the cooler weather. Plants or seeds should be planted in late July to early August. You can also plant your second crop of warm season vegetables now if you haven’t yet to get a longer harvest period and possibly avoid problems with insects and diseases during their peak time.

6. This caller has a rose bush with something eating the leaves off it. What would cause this and how can it be controlled?

A. This could be from a couple of different issues. Japanese beetles will feed on the leaves of roses and cause the leaf to look like lace with little leaf left besides the veins. Rose slugs can do some damage to roses but it looks worse than it is and the feeding should be nearing completion for the year. If you aren’t seeing the insects, it could be rose chafers that feed at night. It could also be from a disease such as black spot. Look for a product that contains an insecticide and fungicide to help with any of these problems. A liquid would be better than a dust.

7. A caller has brown spots in his lawn. What is the problem and how can he fix it?

A. This could be due to either brown spot or dollar spot. These two diseases are quite common this year due to the wet spring and early summer conditions we faced. In a home lawn it isn’t usually necessary to use a fungicides because the fungi don’t kill the lawn and they are sporadic from year to year. It will fade soon and the grass will green back up. These diseases don’t affect the crown of the grass plant so it will easily grow out of it after a few mowings. Through discussion, we learned that his underground sprinkler system waters the lawn from 1am-6am. It was suggested that he do an irrigation audit and move the time for watering forward to 4am-10am. Watering overnight keeps the lawn wet in the cooler, dark environment which is great for disease development.

8. The final caller of the show have sugar maples that leafed out well this year but now the leaves are turning brown and dropping off the tree. What is causing that?

A. This could be from anthracnose, a fungal disease of the tree. It can infect the leaves and cause them to fall from the tree. It could also be from not watering enough now that the rains have reduced or from scorch. Be sure to water the tree and look for damage on the trunk or girdling roots. Look for borer holes as well and treat with imidacloprid if holes are present. It is most likely from an environmental condition, which we cannot change. The tree should be fine.

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