BRIAN PAIGE
DISEASE RECEIVES ALERT BEACON AWARD
BRIAN PAIGE
DISEASE RECEIVES ALERT BEACON AWARD
Rhizoctonia Crown and Root Rot
by Angela Madeiras , UMass Extension Plant Pathologist
The fungus Rhizoctonia solani can cause crown and root rot in a wide range of annuals and perennials . Rhizoctonia is a natural inhabitant of the soil and can survive there indefinitely . It survives as mycelium in infected plants and plant debris and as sclerotia , small masses of hyphae with a protective rind that resists desiccation .
Symptoms of Rhizoctonia infection include stunting , dieback , yellowing or browning of leaves , wilting , brown lesions on the stem near the soil line , plant collapse , and rotted roots and / or crowns . Other pathogens can cause similar symptoms , so an accurate diagnosis is important .
The fungus exists as many different strains that vary by host preference and environmental requirements . Rhizoctonia diseases are favored by high fertility ( especially high nitrogen ) and are more severe on lush , succulent , dense plants . Disease is also favored by high humidity , warm temperatures , frequent watering and / or irrigation , and cloudy , overcast weather . Rhizoctonia tends to like drier soils than other root and crown rotting fungi , but it does require high humidity for growth and disease development .
For management , avoid damaging stems and roots during planting . Soil preparation that minimizes compaction and structural damage will lessen disease severity . Thin plants to improve air circulation where possible . Water in the morning . Drip irrigation is preferable to overhead . Remove infected plants and plant debris and dispose of them in the trash . Registered fungicides include thiophanate-methyl , azoxystrobin , mancozeb , and polyoxin D . Fungicides may help to suppress Rhizoctonia but they are not a substitute for proper site preparation and good cultural conditions .
Since the season is nearly over there is little that can be done to mitigate Rhizoctonia diseases at this point ; however , there are things that can be done next spring in order to prevent disease from recurring . Biological controls may be mixed into the soil prior to planting or applied as a drench to established plants . Labeled products include MycoStop , Actinovate , Cease , Double Nickel , Root Shield , Howler , Serenade , and Stargus . Read product labels and follow all directions carefully . Avoid over-fertilizing . Avoid light , frequent irrigation : water deeply and infrequently as possible without causing moisture stress , preferably in the morning . If symptoms occur , remove and dispose of affected plants and a border of healthy appearing plants .
Reprinted from UMass Hort Notes September 2024 .
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provides care information , recommendations and step-by-step guides . The main con is the free version has ads , but it does not limit the app ’ s other capabilities .
LeafSnap has free and paid tiers . A year subscription is $ 25.99 and a monthly subscription is $ 4.99 .
PlantSnap PlantSnap allows users to identify plants , flowers , cacti , succulents and mushrooms in seconds with the click of a button on their mobile device . It has 600,000 + plants in its searchable database . The app claims it can currently recognize 90 % of all known species of plants and trees .
It has an auto-detect feature that can automatically find the plant in your photo and help you know when to take the picture .
The main con is that in reviews , this app isn ’ t as accurate as some of the other options .
This app has a free seven-day trial , monthly access for $ 2.99 , yearly access for $ 19.99 or lifetime access for $ 59.99 .
Mistakes to Avoid Technology is only as good as the people who use it . The main issue your team might encounter while using plant identification apps is taking poor quality photos . Educate them on how to take images that are in-focus , well-lit and include the key features like leaves or flowers for the best results .
Another mistake is overreliance on the apps . Educating your team on the common plants they ’ ll encounter while working should still be a priority . The apps should merely serve as a stopgap until you bring new hires up to speed .
Stress to your team that these apps are not infallible . Don ’ t ignore the overall context of the environment the plant is in when making identifications . The U . S . Department of Agriculture ( USDA ) PLANTS Database can help you double-check the known distribution of your identified plant .
By Jill Odom . Reprinted from NALP Edge Sept . 27 , 2024
MALP Newsline | Fall 2024 22