Pest Information
Common Name: Cleavers
Family Name: Rubiaceae (Madder Family)
Latin Name: Galium aparine
Other Names: Bedstraw, white hedge, catchweed, scratch grass, sticky Willie, hairif
Provincial Designation: Common
Life Cycle: Annual, Perennial
Mode of Spread: Seed

Detailed Information
Description: Annual herb with prostate or ascending diffusely branched stem. Stem is square with sharp bristly downward pointing hooks growing on corners. Leavers are produced in whorls on the stem usually in groups of 6 to 8. Leaves are pointed at the tip, roughened and are 2.5 – 7.5 cm. long. Flowers are small, white to creamy in color and are produced in axils of upper leaves. Fruits are produced in pairs and separate at maturity. Seeds are gray brown, rough and bristly.
Growth and Development (Life Cycle): Emergence: The main flush of seedlings is in mid spring, with fewer seeds germinating throughout the summer
Seed Production: Cleavers produce large quantities of seeds (300 to 400 seeds/plant)
Seed germination: Newly harvested seed has been reported to germinate readily Optimum temperature for germination varies with age, young seed germinated best between 2 and 10 degrees C, while seed several years old germinated more readily at between 10 and 20 degrees C. Seeds germinate best in the darkness, but one-year-old seed germinate equally well in weak daylight (20% of full daylight). Temperature above 20 degrees C retard germination. On the soil surface, germination is inhibited by light and seeds do not germinate unless covered with soil
Dormancy: Cleavers seeds placed in dry storage develop a long lasting dormancy. Chilling breaks dormancy. Buried seed loses dormancy in the autumn and gradually acquires it again in spring to become totally dormant between May and August. Dormancy is released again during late-summer and early autumn.
Longevity in the soil: Viability in soils is limited to 2 to 3 years
Dispersal: The seeds are dispersed by water and by animals. The fruit surface is covered with hooked bristles that cling to animals and clothing. The seeds survive passage through the digestive systems of cattle, horses, pigs, goats, and birds. Viable seeds have been found in manure.
Reproduction (Dispersal): Only by seed
Economic Importance (Beneficial Aspects): Detrimental: The growth habit of cleaves is particularly damaging in canola and cereals where it clings to and trails around these crops, making proper development and handling of a crop difficult. The seeds of cleaves are a contaminant of rapeseed.
Beneficial: Cleavers has medicinal and therapeutic uses. It has been used for food processing and animal feed. The roasted seeds are said to be one of the best substitutes for coffee, however, its medicinal use as a laxative and as an emetic would suggest that consumption should be in moderation.
Flowering: Flowering timing: Flower appears mainly from July to September.
Flower color: white to creamy in color
Yield Losses: Cleavers at densities of 100 plants per square metre (sq. yd.) can cause a 20% yield reduction in canola.

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Last Modified: August 20, 2013

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