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Publication #SP 37

 

Citron (Citron Melon), Citrullus lanatus (Thunb.) Mats. & Nakai1

David W. Hall, Vernon V. Vandiver, and Jason A. Ferrell2

Classification

Common Name: Citron (Citron Melon)

Scientific Name: Citrullus lanatus (Thunb.) Matsum & Nakai; Citrullis colocynthis (L.) Schrader var. lanatus (Thunb.) Matsum & Nakai

Family: Cucurbitaceae, Cucumber Family

Seedling

The cotyledons are thick, ovate, and shiny green on the surface (Figure 1). The distinctive white venation is obvious. The large cotyledons are about 1.0 cm wide and 1.8 cm long. The first leaves are palmate, or nearly so.

Figure 1. 

Seedling, Citron melon (Citrullus lanatus [Thunb.] Mats. & Nakai).


[Click thumbnail to enlarge.]

Mature Plant

Citron is a monoecious, hairy annual with a climbing or sprawling growth habit (Figure 2). The tendrils are borne to the side of the deeply divided leaves. The three to four pairs of lobes in the leaves are mostly rounded with toothed margins and a rough surface. The flowers are solitary, with the petals being broad and yellow (2-10 mm long). The flower tube is 2-5 mm long. The fruit is a many-seeded berry. It may be light green or be a variegated light and dark green. The pulp is hard with white flesh. The fruit is globose to oblong and is 15-50 cm long. The seeds are greenish with a pitted surface.

Figure 2. 

Mature plant, Citron melon (Citrullus lanatus [Thunb.] Mats. & Nakai).


[Click thumbnail to enlarge.]

History

Citrullus is the diminutive of the Greek word citrus which refers to the fruit. The Latin species name lanatus means wooly and calls attention to the hairs on the stems and leaves.

Habitat

This weed is native to tropical and warm temperate Africa. It is found on sandy soils in waste places, woods, pinelands, and roadsides from Florida to Texas, northward to North Carolina.

Biology

This weed is closely related to the Watermelon which has the same scientific name.

Control

Peanuts

Strongram and/or Valor applied preemergence will provide effective control of citron. All other preemergence herbicides are largely ineffective against this weed. Paraquat + Storm applied at-cracking is effective, but paraquat alone or paraquat + Basagran does not control citron. Postemergence applications of Cadre and 2,4-DB provide good control of citron, but all other postemergence herbicides are ineffective. Cadre and 2,4-DB may be tank-mixed, but it may be best to apply Cadre early followed by 2,4-DB later in the season.

Cotton

Citron is difficult to control with most available preemergence herbicides currently registered in cotton. Cotoran and Staple will provide suppression for approximately 2 to 3 weeks, but season-long control will not be obtained. Postemergence applications of glyphosate or Staple will give good to excellent control, but a tank-mix of glyphosate + Staple will consistently be the most effective treatment. Likewise, postdirected applications that contain glyphosate are the most effective control programs. MSMA combinations (with Direx, Caparol, etc.) that do not contain glyphosate will often result in less than desirable citron control.

Footnotes

1.

This document is SP 37, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date May 1991. Revised February 2010. Reviewed January 2012. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

David W. Hall, former extension botanist, Herbarium, Florida Museum of Natural History; Vernon V. Vandiver, associate professor emeritus, Agronomy Department; and Jason A. Ferrell, assistant professor, Agronomy Department; Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, Dean.