Proc. Fla. State Hort. Soc. 116:240-241. 2003. PEST STATUS OF LEAF-FOOTED BUGS (: ) ON CITRUS IN LOUISIANA

DONALD C. HENNE1 AND SETH J. JOHNSON from the center, with the peel tissue between oil glands be- Department of Entomology coming necrotic (French and Skaria, 1999). 402 Life Sciences Building The Western leaf-footed bug L. zonatus (Dallas) is also LSU Agricultural Center considered a minor pest of citrus in the southwestern U.S., Baton Rouge, LA 70803 but only where they build to high numbers on and then move to citrus (Quayle, 1938). zonatus WAYNE J. BOURGEOIS has not been reported in Florida (Baranowski and Slater, Citrus Research Station 1986) and was not found in Louisiana until the fall of 1997. LSU Agricultural Center is listed as a pest of pomegranate, cotton, Rt. 1, Box 628 citrus, , dates, watermelon and recently on corn in Port Sulphur, LA 70083 Brazil (Essig, 1926; Quayle, 1938; Panizzi 1989). In Louisiana L. zonatus does not appear until late summer. The first collec- Additional index words. Citrus unshi, Leptoglossus zonatus, L. tion of L. zonatus at the Citrus Research Station at Port Sul- phyllopus, Nematospora coryli, hostplant phenology phur in November 1997 was a new state record and represents an eastward range extension for this . Abstract. Since 1998, leaf-footed bugs have been a serious pest Leaf-footed bugs have been an increasing problem on Sat- of Satsuma oranges, Citrus unshi Marcovitch, in Louisiana. sumas in Louisiana from 1999-2001, and were by far the most Leaf-footed bugs typically began feeding on Satsumas in mid- serious pest of Satsumas during 2000 in Louisiana. Popula- August and continued feeding through harvest. Leptoglossus tions were high and widespread from late August until mid- phyllopus (L) and L. zonatus (Dallas) were the dominant spe- October. Many growers had to make three or more insecti- cies collected on citrus. Leaf-footed bugs caused concealed cide applications but still had numerous fruit that were dam- damage to Satsumas through the transmission of the yeast, aged by leaf-footed bugs. Internal symptoms are not Nematospora coryli Peglion. Symptoms of the disease includ- noticeable until the fruit is peeled, which reduces the market- ed a staining, collapsing and drying out of the juice sacs inside ability of Satsumas. the rind. Frequently, the disease resulted in desiccation and a dry rot of one to several wedges or the entire fruit, rendering the fruit unfit for consumption. As the fruit ripened, external Materials and Methods symptoms of feeding punctures and disease were visible on the rind in the form of small 5-10 mm “green islands” as the A visual survey of citrus and other potential host plants of rest of the rind color turned orange. leaf-footed bugs was conducted from March-October 1999- 2001 to determine host plant succession because of wide- Leaf-footed plant bugs have been considered minor citrus spread concealed damage to Satsuma Mandarin orange in pests in the U.S. The leaf-footed bug, Louisiana. A total of one-man hour of observation was made (L.), is considered a minor pest in the eastern and southern at each of six groves in Plaquemines Parish, Louisiana, at two- states, especially on Satsuma Mandarin orange (Ebeling, week intervals. Since leaf-footed bugs are known to utilize a 1959; Quayle, 1938). Leptoglossus phyllopus feeds on a wide va- wide range of hosts; therefore, wild host plants, vegetables riety of plants and has been reported as a pest of a number of and other fruits in and near the orchards were sampled. cultivated crops. In addition to citrus, it feeds on peaches (Snapp, 1948), potato, , sunflower, bean, , egg- Results and Discussion plant, bell pepper, okra, cucurbits, grain, sorghum, blueber- ry, plum, , lyche, pomegranate, loquat, pear, apple, persimmon, oat and to a lesser extent, rye, barley, wheat and The results of our visual surveys are shown in Figs. 1-3. soybean (Mead, 1971). This species tends to aggregate, so Four different species of leaf-footed bugs were collected, but L. phyllopus and L. zonatus were the two dominant species. Lep- that some trees may have many individuals and others only a toglossus phyllopus was dominant in the spring on non-citrus few (Quayle, 1938). Leptoglossus phyllopus was very abundant in hosts; annual sowthistle, Sonchus oleraceus L., spiny thistle, Cir- some orchards in Texas in 1999 attacking ‘Mars’ and Navel sium horridulum Michx., and early-mid summer on mature oranges (French and Skaria, 1999). Symptoms of damage to fruit of ‘Valencia’ oranges Citrus sinensis (L.) Osbeck, kum- ‘Mars’ and Navel oranges first appeared as irregular green quat and tomatoes. During the drought years of 1999 and spots at the feeding sites that gradually turned brown starting 2000 L. phyllopus was more abundant than L. zonatus on Satsu- mas. Leptoglossus phyllopus accounted for 87% (n = 79) and 98% (n = 751) of observations in 1999 and 2000, respectively. The authors would like to thank C. Clark, LSU Agricultural Center, for There was a shift in species dominance in 2001, where L. zona- isolating cultures of N. coryli. Thanks are extended to Drs. Jim Fuxa and Ab- tus accounted for 97% (n = 329) of leaf-footed bugs observed ner Hammond, LSU Agricultural Center, for their helpful comments and on Satsumas. The L. zonatus population increased from six criticisms of an earlier draft of this manuscript. Approved for publication by per man hour of searching in August to a high of 84 per man the Director, Louisiana Agricultural Experiment Station as Manuscript num- ber 03-26-1338. hour of searching on 11 Oct. in an untreated grove. Only one 1Corresponding author. orchard was sampled in late summer to early autumn 2002.

240 Proc. Fla. State Hort. Soc. 116: 2003.

Fig. 1. Leaf-footed Bug Survey 1999, Plaquemines Parish, Louisiana. Fig. 3. Leaf-footed Bug Survey 2001, Plaquemines Parish, Louisiana. Num- Numbers of leaf-footed bugs are an average of three, 20-minute observations. bers of leaf-footed bugs are an average of three, 20-minute observations.

Leptoglossus zonatus accounted for >99% (n = 132) of observa- rind. In Satsuma, the stain that appeared was brown to red- tions made during that period. In 2001 and 2002 summer dish brown in a portion of the juice sacs attacked. Frequently, rainfall was characterized as normal to above normal, and late the disease results in desiccation and a dry rot. External symp- summer hosts of L. phyllopus, such as puncturevine Tribulus toms of the disease were also identified. At the site of the feed- terrestris L, were plentiful. Leptoglossus phyllopus was apparently ing puncture above an infected wedge, the rind displays a feeding on Satsuma because other preferred host plants were “green island effect.” As the fruit ripens and the rind color not available during 1999 and 2000. The only non-Citrus host turns orange, a small area 5-10 mm in diameter around the identified for L. zonatus was Chinese tallow, Triadica sebiferum feeding puncture remains green. This green island effect (L.). Where L. zonatus had a choice it was collected only on could be used by growers to cull fruit infected with Nematospo- early maturing Satsuma varieties, Louisiana Early and Early ra coryli prior to harvest. Two attempts to culture the yeast St. Ann, from August to October and not the mid-season vari- from five L. zonatus mouthparts and digestive systems failed, ety Brown-Select and late season variety Owari. but future research is planned to continue this investigation. Pure cultures of a yeast, Nematospora coryli, were isolated on Leptoglossus zonatus was implicated as the vector of N. coryli to YDC agar plates from Satsuma fruit with early symptoms of the in California (Quayle 1938) and Leptoglossus go- concealed damage. Fruit inoculated with N. coryli from colo- nagra as the vector to citrus in Cuba (Grillo and Alvarez 1983). nies on the YDC plates by a sterile needle developed symp- toms of the disease. The symptoms of the disease include a Literature Cited staining, collapsing and drying out of the juice sacs inside the Baranowski, R. M. and J. A. Slater. 1986. of Florida and Neigh- boring land areas. Vol. 12: Coreidae of Florida. (: Het- eroptera). Florida Dept. of Agr. And Consumer Service. Contribution No. 630 Bureau of Entomology. Gainesville, FL. Ebeling, W. 1959. Subtropical fruit pests. Univ. California Div. Agr. Sci. 436 pp. Essig, E. O. 1926. of western North America. MacMillan, New York. 1035 pp. French, V. and M. Skaria. 1999. Fruit spotting by leaf-footed bugs. Texas A&M Citrus Center Newsletter 17:5. Grillo, H. and M. Alvarez. 1983. Nematospora coryli Peglion (Nematosporace- ae: Hemiascomycetidae) y sus trasmisores en el cultivo des los citricos. Centro Agricola. 10:13-34. Mead, F. M. 1971. Leaf-footed bug, Leptoglossus phyllopus (Hemiptera: Core- idae). Florida Dept. Agr. And Consumer Service. Div. Pl. Ind. Entomol. Circ. 107:1-2. Panizii, A. R. 1989. Desempenho de ninfas e adultos de Leptoglossus zonatus (Dallas, 1852) (Hemiptera: Coreidae) em diferentes alimentos. An. Soc. Entomol. Bras. 18:375-389. Quayle, H. J. 1938. Insects of citrus and other subtropical fruits. Comstock Publishing Co. Ithaca New York. Fig. 2. Leaf-footed Bug Survey 2000, Plaquemines Parish, Louisiana. Num- Snapp, O. I. 1948. Control of sucking bugs that cause deformed peaches. bers of leaf-footed bugs are an average of three, 20-minute observations. J. Econ. Entomol. 41:555-557.

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