Biology of Lasioerythraeus johnstoni (Acari: Erythraeidae), Ectoparasitic and Predaceous on the Tarnished Plant Bug, Lygus lineolaris (Hemiptera: Miridae), and Other Arthropods O. P. YOUNG1 AND W. C. WELBOURN2 Ann. Entomol. Soc. Am. 80: 243-250 (1987) ABSTRACT One hundred fifty-one host records obtained in 1984-85 from Washington County, Miss., are reported for Lasioerythraeus johnstoni Welbourn & Young. Thirteen insect species from three orders are recorded as hosts of the larval stage, with nymphs of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), representing 52% of all records. Attached larval mites were obtained from undisturbed old-field habitats during the period of 20 March-13 September, with most of the records obtained in July. Parasitization levels for some host species were as high as 46%. Of the attached larval mites, >90% occurred on the dorsal head and thorax, usually at a molt suture. In the laboratory, field-collected attached larval mites killed their hosts and detached within 2 d, passed through several nymphal stages, and became adults in ca. 21 d. Both the active deutonymph and adult forms were predaceous on tarnished plant bug nymphs. L. johnstoni appears to have considerable natural control potential for the tarnished plant bug. KEY WORDS ectoparasite, predator, Lasioerythraeus johnstoni, Lygus lineolaris ERYTHRAEIDAE (Acari: Parasitengona) is a large Materials and Methods and cosmopolitan family of mites with predatory Field Sampling Program. From 17 April to 30 postlarval instars preying on ground and aerial ar- September 1984, 28 sites in the Mississippi Delta thropods in many habitats (Krantz 1978). Larvae (Washington County), Miss., were sampled weekly in most erythraeid genera are ectoparasitic on in- by suction (D-Vac). From 20 February to 20 Sep- sects and arachnids. Species in the genera Balaus- tember 1985, 78 sites were sampled intermittently tium, Erythraeus, and Callidosoma are predators by sweep net or suction. The sites all contained or parasites on such economically important pests substantial populations of Erigeron spp. (Compos- as the European red mite, Panonychus ulmi itae), a genus of fleabane asters known to include (Koch); San Jose scale, Quadraspidiotus pernicio- important host plants of the TPB (Young 1986). sus (Comstock); California red scale, Aonidiella Samples were brought into the laboratory and all aurantii (Maskell); apple aphid, Aphis pomi TPB as well as all insect hosts with attached mites DeGeer; and various noctuid and geometrid Lep- were counted and retained alive for further study. idoptera (Ebeling 1934, Whitcomb & Bell 1964, Laboratory Rearing. The life cycle of the Er- Putman 1970, Sharma et al. 1983). ythraeidae (and other Parasitengona) consists of Given the potential importance of this family egg, prelarva, parasitic hexapod larva, calyptostat- of mites, it is unfortunate that little is known about ic protonymph, active predaceous deutonymph, the biology, ecology, and behavior of its members. calyptostatic tritonymph, and active predaceous This is particularly true for the larval and nymph- adult (Grandjean 1938, Johnston & Wacker 1967). al forms because most species are described based Fourteen TPB and three cicadellid early instars on the adult stage and the larval instars and nymphs obtained from site 2 in 1984, each with a single are unknown. The purpose of this report is to pres- attached mite, were confined separately with a slice ent laboratory and field observations on the biol- of snapbean, Phaseolus vulgaris L., in a glass jar ogy and ecology of a newly described mite, La- (60 ml) covered with a fine-mesh organdy cloth. sioerythraeus johnstoni, and to place this Jars were then maintained in an environmental information in the context of the known biology chamber at 26°C, 80% RH, and 14:10 (L:D) pho- of the family Erythraeidae (Welbourn & Young toperiod. Each engorged larval mite was placed 1986). The potential of L. johnstoni as a natural separately in a glass jar (16 ml) with a snap cap control agent for the tarnished plant bug (TPB), following detachment from its host. Each contain- Lygus lineolaris (Palisot de Beauvois), will be dis- er was previously half-filled with a hardened 9:1 cussed. mixture of plaster of paris and activated charcoal, which was slightly moistened (Wharton 1946). Jars were examined twice daily at 0730 and 1600 hours. 1 Southern Field Crop Insect Manage. Lab., ARS-USDA, P.O. After emergence from the inactive protonymph Box 346, Stoneville, MS 38776. stage, each active deutonymph was placed in a - Acarology Lab., Dep. of Entomology, The Ohio State Univ., Columbus, OH 43210. glass jar (60 ml) containing 10 first-instar TPB as 243 244 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 80, no. 2 Table 1. Host records of L. johnstoni Site Collection date No. records Taxon Host stage (1984-85) Hemiptera Miridae L. lineolaris Nymph 1 14 May 2 Nymph 3 16 May 1 Nymph 1 20 May 1 Nymph 1 27 May 3 Nymph 1 24 June 1 Nymph 4 25 June 3 Nymph 1 25 June 1 Nymph 1 3 July 1 Nymph 5 5 July 1 Nymph 2 11 July 11 Nymph 2 12 July 12 Nymph 2 13 July 36 Nymph 2 9 Aug. 1 Nymph 3 9 Aug. 1 Nymph 3 23 Aug. 1 Nymph 1 30 Aug. 2 Nymph 1 13 Sept. 1 Polymerus basalis (Reuter) Nymph 5 5 July 3 Nymph 7 11 July 1 Taylorilygus pallidulus Blan. Nymph 1 5 July 1 Nymph 1 15 July 1 Pseudatomoscelis seriatus (Reuter) Nymph 1 16 May 1 Nymph 1 27 May 1 Anthocoridae Onus insidiosus (Say) Nymph 12 July Lygaeidae Undetermined species Nymph 24 June Pentatomidae Holcostethus sp. Nymph 1 2 Aug. 1 Nymph 1 30 Aug. 1 Podisus maculiventris (Say) Nymph 5 5 July 1 Nymph 5 15 July 1 Rhopalidae Undetermined species Nymph 8 12 July 2 Nymph 2 13 July 1 Nymph 1 15 July 1 Homoptera Aleyrodidae Undetermined species Adult 5 5 July 1 Adult 1 9 Aug. 1 Cicadellidae Undetermined species Nymph 1 20 Mar. 1 Nymph 1 4 Apr. 2 Nymph 6 6 May 1 Nymph 3 24 June 1 Adult 5 5 July 1 Nymph 5 5 July 3 Nymph 2 13 July 3 Nymph 3 15 July 3 Nymph 5 15 July 1 Nymph 2 24 July 3 Nymph 2 9 Aug. 11 Nymph 2 24 Aug. 6 Nymph 2 30 Aug. 10 Undetermined family Nymph 3 27 May 1 Nymph 3 15 July 1 Diptera Undetermined muscoid species Adult 5 July Acari Erythraeidae L. johnstoni Larva 5 July Araneae Micryphantidae Undetermined species Immature 5 July 1 Total 151 March 1987 YOUNG & WELBOURN: BIOLOGY OF L. johnstoni 245 a food source. The jar was again covered with a Table 2. Relative parasitization of tarnished plant bug fine-mesh organdy cloth, placed back in the en- first and second instar nymphs and early instar cicadellid vironmental chamber, and examined twice daily. nymphs by L. johnstoni larvae at site 2 in 1984 When each deutonymph became quiescent upon No. entering the calyptostatic tritonymph stage, it was No. hosts Date Host sampled para- para- placed in one of the same 16-ml glass jars used for sitized sitized the protonymph stage and maintained as before. 11 July TPB 134 11 8.2 After adult emergence, each mite was either pre- Cicadellid 200+ 0 0.0 served in alcohol or offered TPB nymphs for 24 h 12 July TPB 37 12 32.4 and placed in alcohol. Four selected specimens in Cicadellid 300+ 0 0.0 13 July TPB 117 36 30.8 each stage of development were preserved in al- Cicadellid 200+ 3 <1.0 cohol for subsequent identification and descrip- 14 July0 tion. 16 July TPB 10 0 0.0 Cicadellid 100+ 0 0.0 Attachment Sites on Hosts. Thirty-eight TPB 19 July TPB 15 0 0.0 and 40 cicadellid early-instar parasitized nymphs Cicadellid 87 0 0.0 were preserved in alcohol, subsequently examined 21 July" under magnification, and the site of mite attach- 24 July TPB 17 0 0.0 Cicadellid 101 3 3.0 ment recorded. 30 July TPB 185 0 0.0 Cicadellid 23 0 0.0 1 Aug." Results 2 Aug. TPB 11 0 0.0 Cicadellid 13 0 0.0 Field Sampling Program, 1984. Only four of 9 Aug TPB 1 1 100.0 the 28 sites sampled contained larval L. johnstoni Cicadellid 24 11 45.8 attached to TPB nymphs (Table 1). One site also 24 Aug. TPB 0 0 0.0 contained larvae attached to early-instar Cicadel- Cicadellid 13 6 46.2 lidae (Homoptera) nymphs. The 28 sites were of 30 Aug. TPB 0 0 0.0 Cicadellid 876 10 1.5 two major types, roadside margins (20) and old- field habitats (8). All attached mites were obtained " Insecticide application. from four old-field habitats, which are character- ized here. Site 1 was a 2.5-ha fallow field 3 km south- the west by a 50-ha cotton field, and on the south southeast of Leland, Washington County, bor- by a deciduous-tree-lined creek bank. Approxi- dered on the east by a paved road and adjacent mately 20% of the site (the northernmost portion) 32-ha cotton field, on the north by residences, on was occupied by E. strigosus at a plant density of the west by a deciduous-tree-lined creek bank, and five per square meter. on the south by old-field habitat. Although mixed One hundred sixty-seven samples of insects col- grasses predominated, Erigeron strigosus was the lected from Erigeron spp. over 5 mo were exam- principal flowering plant and was scattered ined for attached mites, with 17 samples yielding throughout the field as well as in a nearly homo- positive results.