Petunias dying overnight - Ask Extension
I care for hanging Petunia baskets in the city where I live, they are beautiful and huge. About mid July some of the baskets developed aphids and wor...
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Petunias dying overnight #207582
Asked August 19, 2014, 11:48 AM EDT
I care for hanging Petunia baskets in the city where I live, they are beautiful and huge. About mid July some of the baskets developed aphids and worms but they were successfully treated with a chemical. Recently I've noticed the stems, leaves and flowers on the bottom of some plants have begun to shrivel and die off. It's happening in more of the baskets every day. What's wrong with them. I would hate losing my job (which I've held for 9 years)and the baskets by not being able get this problem under control. Please advise. I water with a full flush everyday when temps are above 80 and fertilize with a 10-30-20 blend full strength once a week and 1/2 strength once a week. I've noticed no fungus spores or large colonies of bugs on the plants.
Clackamas County Oregon
Expert Response
Thank you for your question to Ask an Expert.
The symptoms that you describe with the older stems dying partially matches with the symptoms of one cultural condition and two different diseases:
Over fertilization:
http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/over-fertilization
Is the amount of fertilizer that you are using the same as previous years? Are leaf tips burned? Is there a crust on the soil surface? How much fertilizer per plant are you adding with the full-strength and 1/2 strength applications?
Stem rot:
http://pnwhandbooks.org/plantdisease/petunia-petunia-spp-stem-rot
Are there off-color spots at the base of the stems? Are any of the stems bleached and hollowed? Have any of the stems developed a white mold at the base?
Root rot:
http://pnwhandbooks.org/plantdisease/pansy-viola-spp-thielaviopsis-root-rot
It might be worthwhile to pull a plant out of the soil to examine the root system. Are there darkly colored marks on the root or crown of the plant? This disease is brought on by unfavorable environmental conditions like the heat we have experienced in the last month or so.
Both diseases are spread through spores in the soil. Did you change the potting soil before planting? Did you sterilize the pots before planting? Did you plant certified disease resistant plants? These steps are recommended for next year.
If you want to bring one of the potted plants to the Extension office in Oregon City, OSU staff can help you to diagnose the problem and then provide recommendations for management.
The picture that you sent is dark and does not help to diagnose the problem. Alternatively, you could take additional pictures and send them to the address below.
Please let me know how I can help further.
Weston
The symptoms that you describe with the older stems dying partially matches with the symptoms of one cultural condition and two different diseases:
Over fertilization:
http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/over-fertilization
Is the amount of fertilizer that you are using the same as previous years? Are leaf tips burned? Is there a crust on the soil surface? How much fertilizer per plant are you adding with the full-strength and 1/2 strength applications?
Stem rot:
http://pnwhandbooks.org/plantdisease/petunia-petunia-spp-stem-rot
Are there off-color spots at the base of the stems? Are any of the stems bleached and hollowed? Have any of the stems developed a white mold at the base?
Root rot:
http://pnwhandbooks.org/plantdisease/pansy-viola-spp-thielaviopsis-root-rot
It might be worthwhile to pull a plant out of the soil to examine the root system. Are there darkly colored marks on the root or crown of the plant? This disease is brought on by unfavorable environmental conditions like the heat we have experienced in the last month or so.
Both diseases are spread through spores in the soil. Did you change the potting soil before planting? Did you sterilize the pots before planting? Did you plant certified disease resistant plants? These steps are recommended for next year.
If you want to bring one of the potted plants to the Extension office in Oregon City, OSU staff can help you to diagnose the problem and then provide recommendations for management.
The picture that you sent is dark and does not help to diagnose the problem. Alternatively, you could take additional pictures and send them to the address below.
Please let me know how I can help further.
Weston
