A dense white mycelial web covers the dying clover. The spots rapidly increase in size to several feet in diameter. This mainly occurs from late February through early April and is most severe in rank, ungrazed fields. Sclerotinia, a soil-borne fungal pathogen commonly termed water mold, leads to the appearance of dead, watery vegetation in scattered spots about 6 inches in diameter. Seed treatment does not protect small-seeded legumes varietial and specific susceptibility varies. These usually attack young plants below the soil line, invade plant cells, and kill seedlings rapidly. The causal agents of damping-off disease are the common soil-borne fungi Pythium spp. (1976) detailed several important diseases of clovers. Barnett and Diachun (1985) list 19 classes of virus that affect clovers. Pest Effects, NematodesĪccording to Leath (1985), clovers are afflicted with several diseases, including: (1) internal breakdown, a physiogenic disease that involves the deterioration of pith in the upper crown region (2) 15 major diseases caused by fungal pathogens or complexes thereof and (3) 15 diseases of minor importance, including those caused by fungal and bacterial pathogens. Larvae of alfalfa weevil and clover leaf weevil (green, legless, and about 1/2 inch long) damage growing tips and young leaves in late spring (Murphy et al., 1976). Along the Sierra foothills, a small leaftier caterpillar ties the folded clover leaf together with a web and lives inside, feeding on the leaf. In spring, various phytophagous mites can cause severe local damage. Insects can cause periodic local damage but do not usually eliminate the legume attacked chemical control is usually impractical. Manglitz (1985) wrote that insect pests attacking clovers include clover leaf weevil ( Hypera punctata ), alfalfa weevil ( Hypera postica ), alfalfa caterpillar ( Colias eurytheme Boisduval), green cloverworm ( Plathypena scabra ), omnivorous leaf tier ( Cnephasia longana ), various grasshoppers and crickets, various beetles, yellow clover aphid ( Therioaphis trifolii Monell), pea aphid ( Acyrthosiphon pisum ), blue alfalfa aphid ( Acyrthosiphon kondoi Shinji), clover aphid ( Nearctaphis bakeri ), potato leafhopper ( Empoasca fabae Harris), clover leafhopper ( Aceratagallia sanguinolenta ), meadow spittlebug ( Philaenus spumarius ), clover root curculio ( Sitona hispidulus ), clover root borer ( Hylastinus obscurus ), clover head caterpillar ( Grapholita interstinctana ), lesser clover leaf weevil ( Hypera nigrirostris ), clover head weevil ( Hypera meles ), clover seed weevil ( Tychius picirostris ), clover seed midge ( Dasyneura legumnicola ), and clover seed chalcid ( Bruchophagus platypterus). The native clovers showed low dry matter yield, but good quality, and appeared not to be cyanogenic. repens L.) cultivars 'BR-1-Bage', 'Regal', 'Jacul', and 'Gualba.' The new varieties of white clover appeared promising. (1989) assessed dry matter yield, crude protein percentage, and in vitro dry and organic matter digestibilities for the native Brazilian clovers Trifolium riograndense Burkart (autotetraploid and diploid forms) and T. (1996) in Hopland, Mendocino County, during May following October seeding were (mean +/- S.E.M., Mg/ha): Berseem Clover ('Bigbee') 8.5+/-0.8 Crimson Clover ('Flame') 8.5+/- 1.5 Rose Clover ('Hykon') 6.2+/-1.7 'Koala' Subclover, 9.7+/-1.6 'Mt. Based on those ratings, fertilizer should be applied as follows:Ĭlover above-ground dry biomass yields reported by Bugg et al. Soil phosphorus levels are rated as very low (5 ppm) low (5 to 10 ppm) intermediate (10 to 20 ppm) and high (over 20 ppm). Clover plants growing without sufficient phosphorus are small, with small, dark-green leaves. Many grasslands show phosphorus deficiencies. ![]() ![]() Additional nitrogen increases competition from grass species in newly-seeded pastures and reduces nitrogen fixation. Where soil tests show more than 5 ppm phosphorus, less fertilizer may be used. If the field has not been previously fertilized or the phosphorus is less than 5 ppm, apply about 500 pounds single superphosphate per acre, to supply both phosphorus and readily available sulfur. ![]() The latter can be determined in a commercial soil-testing laboratory by the sodium bicarbonate-extraction soil test. (1976), fertilization at planting time should depend on the previous history of the field and the available soil phosphorus.
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