Poinsettia Solutions PGR Solutions Insect Solutions Disease Solutions Quick Ref. Guide

OHP Marketing Log-in

Damping off can destroy seeds and young seedlings through infection by soil borne pathogens. Pre–emergence damping–off occurs when germinating seeds are attacked and rot before they emerge from the soil. Post emergence damping–off occurs when newly emerged seedlings wilt or collapse. Stems often have necrotic or water–soaked lesions at the soil interface. A pattern of collapsed plants appears as the fungus move out from the area of initial infection.

Several pathogens can cause these diseases, including the water molds (more closely related to algae than fungi) Phytophthora, and Pythium. Root rots are also caused by the true fungi, including Fusarium, Rhizoctonia, Thielaviopsis and Cylindrocladium. It is important to identify the pathogen(s) causing the disease (e.g. Pythium, Phytophthora or one of the true fungi) because the fungicides used for control are different. Many diseases can be caused or spread by an increase of circulated water, sub–irrigation (ebb and flood) systems and over fertilization.

Phytophthora root rot infections appear to be lacking water because the pathogen is destroying the plants’ water conducting ability. Phytophthora diseases affect both woody and herbaceous plants. Spores can remain dormant for a long time just waiting for conditions to be right.

Compass™ O 50 WDG – Strobilurin Fungicide
Apply 1 – 2 ounces per 100 gallons as a drench to wet the upper one–half of the container media

Rhizoctonia stem and root rot diseases are caused by soil borne fungal pathogens. Rhizoctonia can be especially damaging to seedlings causing damping off. Cankers and moist lesions form at the base of infected petioles at the soil interface or on the stems. Rhizoctonia is most severe with high temperatures and moist conditions.

Compass™ O 50 WDG – Strobilurin Fungicide
Apply 0.5 ounce per100 gallons as a drench to wet the upper one–half of the container media

Sextant™ or Chipco® 26019 N/G – Fungicide
Sextant, apply 13 fluid ounces per 100 gallons as a drench at 1–2 pints per square foot
Chipco 26019, apply 6 fluid ounces per 100 gallons as a drench at 1–2 pints per square foot

OHP 6672™ 4.5L or OHP 6672™ 50W – Ornamental Fungicide
OHP 6672 50W, apply 12–16 ounces per 100 gallons at 1–3 pints per square foot
OHP 6672 4.5L, apply 20 fluid ounces per 100 gallons at 1–2 pints per square foot

SoilGardTM 12G – Microbial Fungicide
Mix 1 – 1.5 pounds per cubic yard of container media and incorporate; OR add 0.5 – 2 pounds to 100 gallons of water and drench at 100 gallons per 400 square feet.

Thielaviopsis is another soil borne fungal pathogen. Symptoms can include chlorotic foliage and stunted growth aboveground and the typical decayed roots that exhibit a black or very dark appearance (black root rot). Thielaviopsis can produce basal lesions (generally not as wet as Rhizoctonia). This disease is problematic with plant stress including high pH, cool soil, poor drainage and excess fertilization.

Compass™ O 50 WDG – Strobilurin Fungicide
Apply 1 – 2 ounces per 100 gallons as a drench to wet the upper one–half of the container media

OHP 6672™ 4.5L or OHP 6672™ 50W – Ornamental Fungicide
OHP 6672 50W, apply 12–16 ounces per 100 gallons at 1–3 pints per square foot
OHP 6672 4.5L, apply 20 fluid ounces per 100 gallons at 1–2 pints per square foot