EC59-1831 Plant Diseases : Soil Treatments for Damping-Off

Extension Circular 59-1831 is about plant diseases specifically the soil treatments for damping – off. This includes the fungicides for damping-off, nematicides, soil sterilants, and the precautions

Efek Perendaman Benih dengan Pupuk Hayati terhadap Pertumbuhan Bibit dan Serangan Penyakit Rebah Semai pada Tomat (Solanum lycopersicum)

The use of biofertilizers is part of an environmentally friendly plant cultivation. In order to analyze the effect of soaking seeds with several types of biofertilizers on seedling growth and damping off disease in tomatoes, a greenhouse experiment has been carried out using biofertilizers and the fungicide Propineb as control treatment. The biofertilizers used were mixed biofertilizer (BION-UP), Consortium isolates of tomato rhizosphere bacteria (CITRB), consortium of Azotobacter chrococcum and Trichoderma harzianum (Azoto-Tricho). The results showed that soaking tomato seeds in bioagens solution increased plant height, number of petioles, fresh weight and dry weight of plants, as well as suppressed damping off disease in tomato nursery. The CITRB biofertilizer has a better effect on plant growth and diseases suppression than another biofertilizers and Propineb fungicide. CITRB enable to increase plant height by 49.97%, number of petioles by 60.00%, plant fresh weight by 107.23%, dry weight of plants by 129.41%, and suppress damping off disease by 56.67%. BION-UP, CITRB and Azoto-Tricho were able to suppress damping off disease by 22.22%, 27.78% and 16.67% respectively.  The ability of all biofertilizer to suppress damping off disease incidence were better than Propineb fungicide

Evaluation of indigenous Trichoderma isolates from Manipur as biocontrol agent against Pythium aphanidermatum on common beans

Pythium aphanidermatum is one of the common causal pathogen of damping-off disease of beans (Phaseolus vulgaris L.) grown in Manipur. A total of 110 indigenous Trichoderma isolates obtained from North east India were screened for their biocontrol activity which can inhibit the mycelial growth of P. aphanidermatum, the causal organism of damping-off in beans. Out of the total isolates, 32% of them showed strong antagonistic activity against P. aphanidermatum under in vitro condition and subsequently 20 best isolates were selected based on their mycelial inhibition capacity against P. aphanidermatum for further analysis. Different biocontrol mechanisms such as protease, chitinase, β-1,3-glucanase activity, cellulase and production of volatile and non-volatile compounds were also assayed. Based on their relative biocontrol potency, only three indigenous Trichoderma isolates (T73, T80 and T105) were selected for pot culture experiment against damping-off diseases in common beans. In greenhouse experiment, Trichoderma isolates T-105 significantly reduced the pre- and post-emergence damping-off disease incidence under artificial infection with P. aphanidermatum and showed highest disease control percentage

Pathogenicity study of some seed-borne fungi of onion (Allium cepa L.) from Burkina Faso

Onion production in Burkina Faso faces to several constraints including diseases. Symptoms such as seedling damping-off are currently been observed. Most of the fungi responsible for onion diseases are seed-transmitted but in Burkina Faso, little information on onion seed quality were available. In a previous study, Aspergillus niger, Fusarium oxysporum and Fusarium solani were found to be the main fungi present on onion seeds but their responsibility in the development of seedlings damping-off has not been established. The overall aim of this study is to evaluate in vitro, the effect of these fungi on onion seed germination and coleoptile growth in order to establish this responsibility. Onion seeds were inoculated with mycelium suspension of the fungi concentrated at 13.3 g/ml and incubated for 6 days under appropriates conditions. All the tested fungal isolates had an inhibitory effect on onion seed germination at rates ranging from 31 to 60%. The Fusarium species were the most virulent. Coleoptile length was also reduced by the fungi, leading to significant growth time-lag at rates ranging from 34 to 100%. Aspergillus niger was the most virulent. In conclusion, Aspergillus niger, Fusarium oxysporum and Fusarium solani are responsible of seedling damping-off of onion in Burkina Faso

Microwave Pasteurization of Potting Mixes

A study was conducted to determine if potting soils could be pasteurized with a typical 1200 watt microwave oven. Microwave radiation times varied from 0 to 6.0 minutes. Preliminary results indicated that damping-off diseases could be prevented in tomato seedlings with the use of potting soils pasteurized by microwaves

Use of Seed Coating and Fungicide Seed Treatment in Establishing Alfalfa

Establishing a good stand is an important step in the efficient and profitable production of alfalfa. Site selection, seedbed preparation, seeding method, depth of seeding, and other agronomic factors can affect stand establishment. In some cases, seed and seedling diseases can be a significant problem in alfalfa. Damping-off (caused by Pythium spp. And Phytophthora megasperma) generally is recognized as the primary disease problem affecting alfalfa establishment. Problems due to damping-off can be significant, particularly when alfalfa is planted into poorly drained soils. In addition to site selection, fungicide seed treatment is one way to minimize losses from damping-off. For maximum plant vigor and N-fixing capability, inoculation of alfalfa seed with the appropriate rhizobia bacteria prior to planting is essential. Seed coating is a relatively new development in the alfalfa seed industry. Lime is used as the seed coating base to which rhizobia and possibly fungicide seed treatments are added. Seed coating is intended to increase stand density compared to noncoated seed, but results have been variable

Scouting for soybean seedling diseases in 2000

The relatively dry spring has provided good conditions for controlling postemergence damping-off. Seedling disease problems this season are lighter than usual after soybean emergence. However, the rain in past 2 weeks in some regions of Iowa has been followed with a few reports of seedling diseases. The ISU Plant Disease Clinic also has received samples of infected soybean seedlings. This article discusses some seedling diseases of soybeans that growers may see this season