Eclipta Identification and Control in Peanut C 869
- Full Text
Eric P. Prostko, Extension Agonomist - Weed Science
Published with minor revisions on Mar 14, 2012.
Eclipta is considered to be one of the world's worst weeds. This publication discusses the identification and control of eclipta in peanut.
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Eclipta Identification and Control in Peanut
Eclipta (Eclipta prostrata formerly Eclipta alba) is a broadleaf weed that can occasionally be found in fields throughout the peanut belt. In Georgia, eclipta is not considered to be one of the most common weeds in peanut, but it can be very troublesome in years when environmental conditions (cool, wet) favor its development (Figure 1). Eclipta is considered to be one of the world's worst weeds and has been reported to be a problem in 17 crops in 35 countries. Other names for eclipta include yerba-de-tago and false daisy.
Eclipta plants can grow either prostrate (flat) or erect (upright) up to 36 inches tall (Figure 2). Seedling leaves are ovate to egg-shaped with short, toothed margins (Figure 3). Older leaves are opposite and lanceolate (long and narrow) with toothed margins (Figure 4). Stems are reddish-purple with short, flat, up-turned hairs (Figure 5). Eclipta has round flowers that are green early then white with short rays (Figure 6).
Like many other plants that have become weed problems, eclipta is not native to the United States. It was introduced from Asia. Eclipta is a member of the Compositae or Asteraceae plant family. This is the third most important plant family in terms of the number of weed species and includes plants such as common cocklebur (Xanthium strumarium), common ragweed (Ambrosia artemisiifolia), and bristly starbur (Acanthospermum hispidum).
Eclipta is a summer annual weed that has the potential to produce 17,000 seeds per plant (Figure 8). Eclipta seed can germinate over a wide range of soil temperatures (50 to 95 degrees F) and pH levels (5 to 8). Optimum temperature for germination is 95 degrees F. Eclipta germination is greater in moist soils, so it is most often found in poorly drained or low lying areas of a field and in years of excessive rainfall.
Competition studies to assess the influence of eclipta populations on peanut yield have not been conducted at this time. However, some research has shown that the presence of eclipta in peanut can reduce yields more than 75 percent.
Eclipta can act as a host for Sclerotinia blight (Sclerotinia minor). Although this disease is not present in Georgia, it is common in many other peanut producing states such as North Carolina, Oklahoma, Texas and Virginia. Additionally, eclipta is an alternate host of the southern root-knot nematode (Meloidogyne incognita), which was identified in more than 65 percent of the soil samples analyzed in a recent University of Georgia survey.
Preplant-incorporated or preemergence applications of Strongarm (diclosulam) or a preemergence application of Valor (flumioxazin) provide good to excellent residual control of eclipta. Preemergence herbicides are most effective when followed by at least 0.5 inches of rainfall or irrigation within 7 to 10 days after application. Under extremely dense populations of eclipta, control from a soil-applied herbicide may need to be augmented with a sequential postemergence herbicide application.
Postemergence herbicides that provide adequate control of eclipta include Cobra (lactofen), Basagran (bentazon), Storm (bentazon + acifluorfen), and Ultra Blazer (acifluorfen). These herbicides are most effective if applied to eclipta plants less than 2 inches in height. Postemergence herbicide applications made to eclipta greater than 2 inches often result in reduced control (Table 1).
|Table 1. The influence of herbicide and application timing on eclipta control in peanut.a|
|Herbicideb||Rate/A||Timingc||Eclipta Control (%)d|
|Basagran 4SC||1.5 pts||EPOST||99|
|Blazer 2SC||1 pt||EPOST||79|
|Storm 4SC||1.5 pts||EPOST||97|
|a Adapted from W.J. Grichar, 1997.
b All treatments included Agridex @ 1 qt/A.
c EPOST = early-postemergence when eclipta was <2" tall; LPOST = late-postemergence when eclipta was 3-4" tall.
d Average of 3 years.
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Grichar, W.J., and A.E. Colburn. 1996b. Postemergence control of eclipta (Eclipta prostrata L.) in peanuts (Arachis hypogaea L.). Texas Journal of Agriculture and Natural Resources 9:89-96.
Holm, L.G., D.L. Plucknett, J.V. Pancho, and J.P. Herberger. 1977. The World's Worst Weeds: Distribution and Biology. University Press of Hawaii. Honolulu. 609 pp.
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Sholar, J.R. and J. N. Nickels. 1999. Eclipta (Eclipta prostrata) control programs in peanut. Proceedings of the Southern Weed Science Society 52:63.
USDA, NRCS. 2002. The PLANTS Database, Version 3.5. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
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C 869 |
with minor revisions on
Mar 14, 2012.
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