![]() Temperature: 66° – 68☏ (18° – 20☌) until first set of true leaves. ![]() Lighting for more than two weeks during early plug stages can result in bleaching or yellowing of leaves (photo-oxidation). Supplemental lighting at 350 – 450 foot candles (3,500 – 4,500 lux) for two weeks will help to produce vigorous, strong-stemmed seedlings in regions where light levels are low. Light: Provide 2,500 foot candles (25,000 lux). Media: pH: 6.2 – 6.5 Low pH (1.25, shoot tip abortion may occur. Expect radicle emergence in 3 – 5 days.Ĭover: Seeds may be covered with a light layer of medium vermiculite to maintain moisture levels. Germination: Optimum conditions for seedling development that begins the day the crop is sown until cotyledon expansion. Drought stress will induce early flowering. Specific Flowering Mechanism: Irradiance has no effect. Control is obtained by insect control and removal of diseased plants.Time frame when plants are receptive to flower initiation: Days 12 – 14 2 – 4 leaves present.įlowering Type: Day-neutral plant – will flower regardless of daylength. Secondary shoots are formed profusely on infected plants. Yellows may attack only a portion of the plant. Affected plants do not wilt or die, but have a spindly type growth which detracts from the plants overall appearance. ![]() As the chlorosis becomes severe, defoliation occurs. Fungicides should be used at the first sign of disease and continued on a 7-14 day schedule.Īster Yellows (mycoplasma): First symptoms are observed as a yellowing or chlorotic appearance along the veins of young leaves. Use rust resistant varieties when available. Alternate host is pine where it produces a blister rust on the needles. In severe cases, foliage turns yellow and dies. Rust (fungus – Coleosporium solidaginis): Orange-red pustules form on the underside of leaves. This problem can be prevented by using nematode-free planting stock and a sterilized potting medium. Root Knot (nematode – Meloidogyne spp.): This nematode causes knots to form on roots. Chemical control may be only partially effective. These become clear with age and may run together to form larger spots. begoniae): Small blister-like spots appear on leaves. This problem is occasional in nature but may occur when environmental conditions are ideal for disease development.īacterial Spot (bacterium – Xanthomonas campestris, pv. Powdery Mildew (fungus – Erysiphe cichoracearum): Affected leaves have a white powdery substance on the upper surfaces. Change the location of potted plants if conditions are overly wet and use appropriate protectant fungicides. Most leaf spotting fungi thrive under high moisture conditions. Leaf Spots (fungi – several): Brown spots appear on foliage and reduce plant vigor. Growers should be sure to start with disease-free cuttings, use a sterilized medium and keep the growing area free of any type of weak or decaying plant material that might serve as a food source for the fungus. This disease is especially severe under greenhouse conditions where begonias are propagated. In advanced stages all tissues may be penetrated by the fungus. Affected plants decline rapidly with stems and leaves developing brown, water-soaked lesions. Use cuttings from healthy plants only.īotrytis Blight and Stem Rot (fungus – Botrytis cinerea): This fungus is most severe when temperatures are cool and moisture levels are high. Fungi responsible for this condition may be introduced on cuttings or be present in soil. This problem is often severe when cuttings are placed in beds for rooting. and others): Affected plants wilt and break over at the soil line due to decayed spots being formed on stems. Stem and Root Rot (fungi – Pythium spp., Rhizoctonia spp.
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