Quick Weed

Galinsoga quadriradiata is highly competitive and can spread quickly, often being the dominant species in a field. It is causing considerable economic impact in cropping systems, greenhouses, gardens and nurseries.

Galinsoga quadriradiata is a species of flowering plant in the daisy family which is known by several common names, including shaggy soldier, Peruvian daisy, hairy galinsoga, and fringed quickweed. G. quadriradiata is a fast-growing annual herb with the capacity to invade agricultural and other disturbed areas in most temperate and subtropical regions of the world.

It is highly competitive and can spread quickly, often being the dominant species in a field. It is causing considerable economic impact in cropping systems, greenhouses, gardens and nurseries. Its presence may reduce yields up to 10-50% in fields planted with vegetables and crops areas. Hairy galinsoga is considered a weed throughout its native and introduced range.

Botanical description.

  • Roots.

The roots form a fibrous root system.

  • Leaves.

Leaves are up to 2½ inches long and 2 inches wide, coarsely toothed, sparsely to densely hairy, with a pointed tip and somewhat rounded or tapering base, oppositely attached. There are 3 distinct veins radiating from the base of the leaf. Leaf stalks are up to 1½ inches long near the base of the plant; becoming shorter as leaves ascend the stem; leaves in the upper plant are stalk-less or nearly so.

  • Stem.

Stems are densely hairy and heavily branched with a height of up to 60cm.

  • Flowers.

Flowers are at the end of hairy stalks arising from the leaf axils in the upper plant and at the tips of branching stems. Individual flowers are about ¼ inch across with 4 to 8 (usually 5) white rays (petals). The center disk flowers are golden yellow.

  • Fruit.

Both the ray and disk flowers produce a dry seed, with 5 or more narrow scales attached at the tip, each scale fringed around the edges and with an awn at the tip.

Dispersal

It can be dispersed by wind, animals, or sometimes water in addition to the hairy nature, which assists in wind dispersal, achenes are covered with short stiff hairs that may cling to the fur of animals.

Dispersal by human activities, such as movement of soil or plants can be very important in the dispersal of this species. The most effective means of dispersal is believed to be seedlings inadvertently grown in nurseries or commercial greenhouses.

Environment requirement.

Quick weed is adapted to warm climates and heavy nitrogen rich and clayey soils and requires a PH range of 5-7.4.  An average rainfall range of between 600-1200mm which is evenly distributed throughout the season favors its growth. Requires an optimum temperature of between 18-27°C.

Habitat

In much of its introduced range, it can be found in gardens, greenhouses, agricultural lands, roadsides, railways, and other disturbed areas, essentially in association with any form of human development.

Crops mostly affected by quick weed include:-

  • Maize.
  • Wheat.
  • Vegetables.
  • Onions
  • Carrots etc.

Disadvantages of the weed in cropped areas.

  • Its presence reduces yields by about 10-50%.
  • It acts as an alternative host for many insects, viruses and nematodes which affect crop species.
  • Takes up nutrients that are essential for cultivated crops.
  • Its high leaf surface area can shade out cultivated plants.
  • It leads to high cost of production.
  • Results to blockage of drainage channels.

Managment.

Cultural methods.

  • Prevention is the best mechanism to tackle the weed hence the need to avoid introducing the weed in in affected areas.
  • Crop rotation with crops such as corn and tomato.
  • The use of summer cover crops such as sorghum suppress its growth and spread.
  • Regular combating with how’s always proves to be successful.
  • Early tillage so as to burry seeds may be useful since the seeds germinate best in lightly disturbed not deeper than 2-3cm soils.

Chemical Control.

This proves to be most effective way of controlling the weed by the use of chemicals such as 2, 4-D, Paraquat and Glyphosate.

At Greenlife we provide CLAMPDOWN 200mls/20L which is a systemic non selective herbicide to be applied in agriculture and non-cropped areas when the weed is actively growing. Farmers need to use clean water to improve on its efficacy.

AGROMINE 120mls/20L which is a systemic selective post emergence herbicide, can also be used to control the weed in maize, rice and wheat field.

HOTLINE 50mls/20L offers excellent results against the weed when it is 2-3 leaf stage. It can be applied as a pre or post- emergent herbicide in carrots. Rain or irrigation is needed to activate the herbicide.

COMMANDER 50mls/20L which is a contact selective herbicide which can be used as a pre or post emergent herbicide which inhibit chlorophyll enzyme production resulting in accumulation of chemicals leading to the disruption of cell membrane integrity in the presence of light. It can be used in onion fields 2-3 weeks after transplanting.

Last updated on Saturday, January 14, 2023 at 11:25 pm

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