Xtremehorticulture

Watch Out for Deadly Fireblight on European Pear, Asian Pear and Quince

Frequently I see this problem pop up on fruit trees in May or June. Readers pear tree Q. I have a pear tree which is about 10 years old.  Up until this year, it has been pretty healthy.  This spring it got a disease. I am hoping you can identify it for me from these pictures and tell me what I can do to treat it so that it won’t be a problem in the future.             I thought at first it might be fireblight but it is not with the new growth.  It seems to have attacked all the places where there would have been fruit. I have inserted pictures for you and hope that these are helpful. It is not receiving any overhead spray.  It is watered with a drip system.    A. This is fire blight. This is a bacterial disease which is more rare than fungal diseases on plants. One way it is spread is through the flowers either by blowing wind during rainy weather or by pollinators such as honey bees.             Flowers of apple and pear come from spurs which are short shoots on older wood. If the disease enters through the flower then it will spread through the older growth and into the new growth if it is present. It does not necessarily have to attack new growth. Fireblight in pear             It can be seen on older growth as well. On new growth if it is present it will show the textbook picture of shepherds hook which I posted on my blog. If new growth was not present then it will simply die back and demonstrate a blackened, scorched, fire appearance.             This disease is extremely virulent and must remove as soon as possible from the tree and the growing area. Cut out the infected limb to 12 inches below the visible infection. Sterilize pruning instruments with a dilution of bleach and water both before and after the cut has been made.             Put the cut limb into a plastic bag, tie the bag and immediately put it into the trash. Do not try to mulch or compost this infected limb. Oil your pruning tools after you disinfect them with bleach so they don’t rust. Classic fireblight shepardshook and black scorched fire symptoms             Wash your hands after you have finished pruning. This disease is fairly rare here due to our isolation from orchards and low humidity. It attacks European pears like Bartlett, all Asian pears and Quince but does not damage Keifer pear. I hope this helps.

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Rosemary Bush Very Susceptible to Dieback if Overwatered

Rosemary dieback from reader Q. Can you diagnose what is wrong with my rosemary bush?  We have two rosemary bushes which are less than three-feet apart.  One is beautiful; the other has die-back in the center.  The one that has the die-back was replaced last year because the previous one had the same problem.      Both of these plants receive the same water and the same fertilizer.  When I replaced the rosemary plant last year, I did a 50/50 mix of compost and native soil.  I don’t see any pests on either of the plants.  Any suggestions? A. I looked at the pictures. There are no specific pests that would cause this type of damage on rosemary. The most likely culprits would be physical damage to the stems (broken stems) or root rot or collar rot from either planting it too deeply or keeping the soil around the one with dieback too wet. Healthy rosemary of reader             If the soil was heavily amended with mulch or compost and it was planted in this then it is possible it could have been planted too deeply while the other one was not. Sometimes plants will sink in the planting hole if the soil is too “fluffy” at the time of planting.             This sinking and soil consequently coming in contact with the stem due to follow-up waterings, can cause the main stem or side stems to decay and then entire stems can dieback.             I would carefully lift the plant out with a shovel and examine the main stem or trunk and side stems and see if they were planted too deeply. Rosemary is very susceptible to collar rot or keeping the soil too wet. If the stems are rotten, dispose and replant in a new location.

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