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Diseases

August 13, 2016
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We have definitely had a wet summer in Arkansas. We have seen a lot of insects, diseases and weeds, and I have seen two diseases that were new to me–and I have been doing this a long time.

The first was on figs. fig souring aug9 16 fig souring aug16Fig splitting can be caused by uneven moisture, just like with tomatoes, but I got some pictures in with the bottom end of the fig turning white and rotting.  This is a problem called souring.  It can occur from a small beetle entering the fruit or rain.  In this case, think of the hard, pounding rains we have been getting. When moisture enters the eye it can sour–ruining that fruit.  You may see some tiny bubbling  coming out of the fruit and a sour, fermented smell.  The key is to harvest frequently, removing any damaged fruits. If you leave them on the tree, ants, wasps and other insects will be attracted which is not something you want.  I guess we don’t see it too often since we rarely have frequent rains in late summer in Arkansas.

The second interesting picture came in yesterday.  hawthorne with cedar quince rust.aug16  I looked at it on my phone and thought it was a buttonbush fruit.  When I sent it to my computer I knew it was a hawthorn tree, but had never seen the fruit looking like that–and not a spot on the foliage.  The problem is Cedar Quince rust.  This disease is closely related to Cedar-apple rust but whereas that disease causes spots on the foliage and fruit, cedar-quince rust mainly attacks the fruits.  It can also cause swollen galls on the stems the fruit is attached to and occasionally galls on a leaf which is a resistance reaction to the leaf infection.  The cedar host is predominately junipers, and mainly Eastern red cedar (Juniperus virginiana).  In the spring, the junipers will have this orange growth on it–cedar quince rust on junipers  The spores from this will fly and attack members of the rose family including apple, crabapple, pears, quince, hawthorn, serviceberry, mayhaw, flowering quince, cotoneaster, and photinia.

Young branches and fruit (not leaves) are usually infected and symptoms vary widely among the various hosts. On hawthorn, the pinkish aecia (fruiting body tubes) occur mainly on branches, thorns, and fruit. Hawthorn and serviceberry fruit often becomes heavily covered with these fruiting bodies called aecia. Here is what it looked like earlier this summer on a mayhaw in Saline County: mayhaw with cedar quince rust gall on leaf mayhaw with cedar quince rust.aug16  If you see infection on small branches, cedar quince rust gall on stem of mayhawit will usually become a perennial cankers that expand each growing season. Often the most infected branches are girdled by the canker during the second season, causing that branch to die back.  When you see the disease the damage is done and sprays are ineffective. All you can do now is prune out cankers and remove as much of the infected fruit  as possible.  Good sanitation this fall will also help.  Sprays are only effective when the disease is active on the cedar trees, so timing of a general fungicide in the spring can prevent infection of your apples, mayhaws and hawthorn.

3 Comments leave one →
  1. August 13, 2016 12:34 pm

    Hi Janet,

    We are growing milkweed for the Monarchs for the second year. This year they have been inundated with a beautiful, red and orange bug. Can you give me some advice please? Will they kill the plant? Can I get rid of them without compromising the life cycle of the butterflies?

    Thanks,

    Candee Teitel Oh Behave Dog School http://www.ohbehave-dogschool.com 501-920-2520 Cell

    ________________________________

    uamg posted: “We have definitely had a wet summer in Arkansas. We have seen a lot of insects, diseases and weeds, and I have seen two diseases that were new to me–and I have been doing this a long time. The first was on figs. Fig splitting can be caused by uneven “

    • uamg permalink
      August 15, 2016 6:49 am

      It is the milkweed bug and they are common every year. They do feed on the milkweed plant sucking sap out of the leaves, stems and seed pods. Knocking them down with a spray of water or using insecticidal soap can help, but be careful with insecticides as they can harm the caterpillars and butterflies that you are trying to attack.

  2. dismith11 permalink
    August 14, 2016 12:40 pm

    Your picture are wonderful. You truly are a treassure.

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