Crop Rotations and Common Rootrot in Wheat

Abstract

ABST ACTIn a 5-year study of common rootrot of wheat in rotations at .Indian g"ta, S"it "t"h&;;, disease ratings were recorded three times -each crop r"rrori r"a isolations were made

Sporulation of Bipolaris sorokiniana on the crowns of crop plants grown in Saskatchewan

“…Spomlation on annual cereal crops uod^ *L"utgtuss species would have contributed enough conidia to-have increased the inoculum density in soil' Sporulation on the other crops would have little effect on inoculum density, as the numbers of conidia produced are far less than either the density needed for maximum infection or the number needed to replace the annual loss in conidia. Ledingham (1961) found conidial numbers decreased by an average of 22%o over the winter period. In fields plantei to wheai soil populations declined from a high of 275 conidia 5l of soil-in the fall to 145 in the spring, and in the fallow fields they dropped from 70 to 35 following a summer and winter period (Chinn 1965).…”

“…In fields plantei to wheai soil populations declined from a high of 275 conidia 5l of soil-in the fall to 145 in the spring, and in the fallow fields they dropped from 70 to 35 following a summer and winter period (Chinn 1965). Ledingham (1961) estimated that conidial populations of 20-30 5l of soil were needed to cause severe infection. In a growth room, maximum disease occulred on wheat and barley with 10-120 conidia cm-3 in the rooting medium (Duczek et al 1985)'…”

Efeito de práticas culturais sobre o rendimento e outras características agronômicas de trigo

“…Os valores mais elevados de severidade do mal-do-pé e de podridão-comum de raízes, ocorreram na monocultura de trigo, em comparação com um inverno e com dois invernos sem essa gramínea, demonstrando o efeito positivo da rotação com espécies não suscetíveis. LEDINGHAN (1961), no Canadá, constatou valores mais elevados de severidade da podridão-comum de raízes de trigo que ocorreram em monocultura (68 %) e em um inverno sem trigo (64 %), em comparação a dois invernos (37 %), a três invernos (34 %) e a cinco invernos (14 %) sem esse cereal. Mediante esses resultados, houve decréscimo da doença proporcionalmente ao aumento de anos de rotação de trigo.…”

“…De acordo com esses mesmos autores, a rotação de culturas permite produzir e estabilizar o rendimento de grãos pela diversificação de espécies. LEDINGHAN (1961), no Canadá, verificou em monocultura de trigo valores mais elevados de severidade de podridão-comum, em comparação a um inverno, a dois invernos, a três invernos e a cinco invernos sem esse cereal. SLOPE et al (1973), na Inglaterra, observaram diferentes valores de severidade do mal-do-pé entre monocultura e dois invernos sem trigo.…”

The presence and effects of seed-borne and soil-borneDrechslern sorokinianaon barley in New Zealand

“…Work in Canada (Ledingham 1961;Chinn 1976) has shown that rotation using crops other than cereals can reduce soil-borne infection levels. In Manawatu-Rangitikei, barley is rarely grown in the same area more than twice in succession, a factor which may have contributed to a lack of population build-up.…”