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Agricultural Experiment Station Technical Bulletins SDSU Agricultural Experiment Station

1966 Plant Feeding Mites of South Dakota Leland D. White

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Recommended Citation White, Leland D., "Plant Feeding Mites of South Dakota" (1966). Agricultural Experiment Station Technical Bulletins. 38. http://openprairie.sdstate.edu/agexperimentsta_tb/38

This Article is brought to you for free and open access by the SDSU Agricultural Experiment Station at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Agricultural Experiment Station Technical Bulletins by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. Technical Bulletin 27 May 1966

Plant Feeding Mites of South Dakota

Entomology-Zoology Department Agricultural Experiment Station South Dakota State University, Brookings ACKNOWLEDGMENTS

Appreciation is extended to: E. W. Baker for assistance in identification of Tetranychidae; H . H. Keifer, who identified specimens of Eriophy­ idae; C. A. Taylor, South Dakota State Univer­ sity plant taxonomist, for assistance in preparation of host-plant scientific names and identification of selected host plants; research assistants, S. A. Johnson, H. C. Schroeder, and G. H. Schwebach; faculty members of the South Dakota State Uni­ versity Entomology-Zoology Department; and to other University staff members who made direct and indirect contributions during this study. TABLE OF CONTENTS

Page Introduction ------·------3 Taxonomic status of the mites ______4 Determination of species ______4

Collecting and Mounting Methods ______5 Eriophyid preparation and mounting media______6

Economic Importance ------7 Plant feeding ------7 Plant diseases and mites ______7

Distribution and Biology ______·------.·------·------9 Tetranychidae ------9 Geographic distribution ------9 Biology ------9 Eriophyidae ------9 Geographic distribution ------9 Biology ------9 Tarsonemidae ------10 Geographic distribution ------· -- -·· ·------10 Biology ------·------10

Discussion of the Species ______------______------·· · 11

T etranychidae ------11 Bryobia ______--···-·--··· ______------·-·-· ______------______15 Bryobia praetiosa ------·------·------··------15 B ryobia ru briocu/ us ------· ______·------____ .. --·------16 Petrohia ------··------·- 18 Petrohia /atens ------18 Panonychus ______------·------·------··------··--- ··· ______.. ·------______20 Panonychus ulmi ------·------21 Schizotetranychus ------__ 23 Schizo tetran yeh us el ym us ------______23 1 TABLE OF CONTENTS (Continued)

Page Eotetranyehus ------24 Eotetranye h us populi ------· __ ·------24 Eotetranye h us matth yssei ------26 Eotetranyehus ( new species) ------· ------29 Oligonyehus ------29 0 ligonye h us pratensis ------·------31 Olt'gon ye h us bieolor ------31 Oligonyehus ( new species) ------33 T etranye hus ------33 T etran ye h us telarius ------· ______·------35 T etran ye h us sinhai ------39 T etran ye h us medanieli ------·------41 T etran ye h us eanadensis ------·------41 Eriophyidae ------· ------46 Abacarus hystrix ______,, ______46

Aeulus ( ? ) dubius ------48 Aeulus mekenziei ------···------49 Aceria tulipae ------49 A baearus ( new species) ------· ·------·---- ·--·------52 T arsonemidae ------______------· ______52 Steneotarsonemus ______-· ---·----- ___ -· ·------· ------____ _-----·------·------56 Steneotarsonemus hyaleos ______. -· 56 Miscellaneous Mite Collections ___ _ ·-- -· __ ------· __ __ ·---·--· ___ __ -·------· __ __ _ 57 Mesostigmata ______..... ______------··-----·· · __ --·-- _---·-·- -- . 57 Trombidiformes __ ___ ------·------·--- ·- ---··------·- -- ______.. 58 Tydeidae ------·- --·------· ______.. ______------58 Stigmaeidae ------·--·------·------·------·------58 Erythraeidae ------·-··------·------· ··------58 Sareoptiformes ------56 Literature Cited ------59 2 Plant Feeding Mites of South Dakota

By LELAND D. WHITE, Assistant Professor, Entomology-Zoology

INTRODUCTION

This phytophagous mite study is It is difficult to estimate an an­ the first of its kind in South Dako­ nual dollar loss to South Dakota ta. Previous records of identified agriculture due to plant feeding species from this state are practi­ mites. However, these pests are of cally unknown. major concern to the national agri­ The economic importance of phy­ cultural economy and as such share tophagous mites, their distribution with insects a position of pest im­ and importance in surrounding portance to the economy of South states is a well documented fact. Dakota. When one considers this plus the Plant feeding mites cause dam­ fact that South Dakota is one of the age principally by direct feeding, major agricultural states, the ne­ although a few species are also cessity for some beginning towards known to transmit serious plant identifying the plant feeding mites virus diseases. Wheat streak mosaic and determining their distribution disease is the only mite-vectored and host plants is obvious as an plant disease reported in South Da­ essential start for any future control kota, although others are under program. The study period was too suspect. brief to prepare a complete pic­ This bulletin includes: (1) spe­ ture of plant feeding mites in cies of plant feeding mites collect­ South Dakota, but hopefully it will ed in past years in South Dakota serve as an effective springboard and reported in the state insect for future work. survey reports, and (2) systematic 3 phytophagous mite collections since plant feeding forms. Of these two, 1964 as part of South Dakota Exper­ the principal suborder containing iment Station project No. 433. important and large numbers of phytophagous species is Trombidi­ Taxonomic Status of the Mites formes. Therefore, emphasis in this Mites, like insects, are Arthro­ paper will be restricted to species pods, but beyond this are not tax­ of Trombidiformes collected in onomically grouped. They are plac­ South Dakota. These species are ed in the class Arachnida with the contained in the families Tetrany­ spiders and other eight legged ar­ chidae (spider mites), Eriophyi­ thropods, whereas insects are plac­ dae (eriophyids, gall, blister, rust, ed in the class Insecta. The order Acarina includes the suborders: or bud mites), and Tarsonemidae Ixodides (ticks), Onychopalpida (tarsonemids). (mites-mostly predators), Mesos­ tigmata (mites - divided among Determination of Species plant feeders, parasites and sca­ Identifications of all Tetranychi­ vengers), Sacroptiformes (mites­ dae in this study have been made divided among plant feeders, par­ and/ or verified by Dr. E. W. Bak­ asites and scavengers), and Trom­ er. H. H. Keifer provided deter­ bidiformes (mites-includes plant minations for all Eriophyidae. In feeders, parasites and predators). the case of Tarsonemidae, the au­ Of the four suborders containing thor has attempted the few deter­ mites, only two contain well known minations required.

4 COLLECTING AND MOUNTING METHODS

Plant feeding mites are so small were removed with a teasing nee­ they are often overlooked by the dle or brush and placed in vials of untrained observer. Thus their pres- 70% alcohol along with a com­ ence frequently remains undetected pleted collection label. When time until they build up in numbers suf- or weather prevented mite removal ficient to cause grossly observable in the field, the infested leaves populations and/ or symptoms of and completed label were placed feeding and damage to the plant. in plastic bags and stored in an ice However, with virus vectoring chest for later transfer to alcohol mites the gross expression of dis- vials. If cool temperatures were ease symptoms is not dependent maintained, the mites would re­ on population density. We often main viable in the bags for several used these symptoms in locating days. favorable collecting areas and host There are a number of mounting plants. media available for slide prepara- In the field, each collection was tions of spider mites, but the most carefully recorded showing host practical one for this work was plant, date, county, collector and Hoyer's. It is easy to make and use, population density estimates. When clears the specimens well, and ex­ time and weather permitted, field cept for the more arid parts of the examinations of the leaves were country makes a good transparent made using a standard binocular and reasonably permanent mount. dissection microscope. The mites In drier areas the slides can be 5 ringed with Zutt to prevent crys­ Suggested use of the eriophyid talization of the medium. mounting media: The Eriophyidae were collected 1. Place mites or infested plant and mounted similar to the other parts in preparatory medium and mites. Subsequent results showing some inadequate clearing and heat until transparent, that is, specimen shrinkage suggested an until tlie soft inner parts of the improvement was needed in col­ mites are dissolved. lection and mounting of the erio­ 2. Transfer to wash medium until phyids. The authority in this field, excess of No. 1 is gone. Keifer ( 1965) , suggested dry stor­ age, followed by a sugar-alcohol 3. Transfer to formaldehyde me­ preservation and wash medium, diuJTI, place cover slip, label with final mounting in a special slide. It is well to add some ka­ medium. pok or cotton fibers to the drop of final medium on the slide be­ Eriophyid Preparation and fore placing coverslip. This pre­ Mounting Media vents crushing the mites which causes a disadvantageous distor­ Preparatory medium tion. Sorbitol 1 gram The lateral profile of the aede­ Chloral hydrate 3 grams agus is of prime importance in spe­ Resorcinol 0.1 gram cies determination of many spider Phenol 0.25 c.c mites since interspecific differences Iodine 0.1 gram between females are often indis­ Water 2 cc tinguishable. To accomplish this, Glycerin 0.25 cc the male adults should be mount­ ed singly. After several days (time Wash medium varies with relative humidity) the medium will be partially hardened Sorbitol 1.0 gram so that lateral pressure against the Chloral hydrate 4.0 grams or edge of the coverslip will rotate 3.5 grams the specimen onto its side. This Phenol 0.25 cc rolling action extrudes the aedea­ KI 0.1 gram gus and makes a permanent later­ Iodine 0.1 gram al mount. Water 2 cc Most species determinations re­ quire the use of phase microscopy Final medium and oil immersion. Thus slide pre­ Sorbitol 1.0 gram parations should be relatively shal­ Chloral hydrate 5.0 grams low and visual scanning area re­ or 4.0 grams duced. To accomplish this, the use Phenol 0.20 cc of circular 12-15 mm. diameter KI 0.1 gram and No. I! thickness cover slips Iodine 0.15 gram is recommended. The amount of Formaldehyde sol. ( 37%) 2 cc mounting medium required will 6 vary with size and thickness of aid to reduce the scanning area, specimens, but should not exceed place small india ink circles on the minimum amount necessary to the underside of the slide around fill the coverslip area. As a final each specimen.

ECONOMIC IMPORTANCE

Although there are some excep­ Plant Diseases and Mites tions, virtually all mite damage to The spider mites are only now plants results from direct feeding being seriously investigated as pos­ and disease vectoring by various sible vectors of plant disease vir­ species from the families Tetrany­ uses. Moskovetz (1940) reported chidae, Eriophyidae, and Tarso­ T etranychus telarius ( two-spotted nemidae. spider mite) as a vector of a virus disease on cotton. The two-spotted Plant Feeding spider mite has also been reported as a vector of Y virus on potatoes, It is doubtful a plant species (Schulz, 1963). A recently describ­ exists that is not a potential or ed spider mite, T. sinhai, ( Baker, has not served as food supply for 1962), is also suspected of trans­ one or more of the plant feeding mitting a virus disease in wheat mites. Of the many phytophagous and barley, (Wallace and Sinha, mite species, the most economical­ 1961). However, the reality and ly important ones are found in the economic impact of these diseases spider-mite family Tetranychidae. in natural field conditions is as yet These mites feed, and therefore undetermined. damage the plant, by piercing the On the basis of present know­ leaves (usually the underside) ledge, the only mites of economic with their styletlike chilicerae (fig­ importance in the spread of plant ure 1) and withdrawing the sap. diseases are species of the family This action results in removal of Eriophyidae. Eriophyids (also chlorophyl giving the leaves a pale known as gall mites, blister mites, mottled appearance. As feeding rust mites, or bud mites) are known damage intensifies the leaves to transmit seven different plant brown, wilt, die and drop. virus diseases. But of this number, The eriophyids and tarsonemids only one disease, wheat streak are also plant feeders. However, mosaic, is reported in South Dako­ the small specimen size of both ta. Symptoms of the disease are too families and relative scarcity of the generalized to assure field identifi­ tarsonemids reduces their econom­ cation, but include a greenish mot­ ic importance as plant feeding tling or streakirrg of the wheat pests in comparison with the spi­ leaves and general stunting of plant der mites. Damage from feeding, growth. Final determination of the when evident, is similar to that disease requires laboratory control­ caused by the spider mites. led transmission tests. 7 Figure 1. Cheliceral and opisthomal venters of Tetranychidae: (A) styfophore and chelicerae of T etranychus telarius; opisthomal venters; (B) female of Petrobia harti; (C) female of telarius; and (D) male of T. telarius. (From Pritchard & Baker, 1955.) 8 DISTRIBUTION AND BIOLOGY

T etranychidae temperature and humidity differ­ Geographic distribution ences. An average for optimum spider mite development from egg The family Tetranychidae (spi­ der mites) contains the best known to adult is 8-11 days. and most economically important Developmental stages are egg, species among plant feeding mites. six-legged larva, quiescent pre­ This family is cosmopolitan in dis­ protonymph, eight - legged proton­ tribution and is recorded as a dam­ ymph, quiescent pre-deutonymph, aging pest on more native and deutonymph, quiescent pre-adult, cultivated plant hosts than any and adult. other arachnid. Biology Eriophyidae There are numerous and detail­ Geographic distribution ed studies on the biology of many The microscopic size of eriophyids of the spider mites. From these (average about 12 mm. in length) studies emerge some basic life his­ has resulted in a paucity of infor­ tory similarities. Adult males do mation regarding their known not commonly survive winter con­ world distribution. Keifer (1952) re­ ditions in the field. The most com­ ports that with the exception of mon overwintering stage is the egg, Europe, Java and California the although clover mites (Bryobia eriophyid areas of the world are es­ praetiosa) are reported to over­ sentially unknown. winter in all stages (Morgan & Anderson, 1958). Biology Parthenogenetic and sexual re- Detailed life histories of nearly production are commonly reported all eriophyids are lacking. How­ within species of Tetranychidae. ever, Slykhuis (1955), Staples and Parthenogenetic reproduction is Allington (1956), and Rosario and also arrhenotokous. Reeves (1963) Sill (1964) have provided excellent reports male production as invar- life history studies on Aceria tuli­ iably the result of unfertilized eggs pae ( K). These and other frag­ even when mating occurs. In typ- mentary reports have provided in­ ical populations there is a prepond- formation for a generalized life his­ erance of females to males. tory presentation which is at least Considerable intra- and inter- representative of the wheat curl specific variation has been report- mite in South Dakota. ed for developmental times of each Approximately twelve eggs are stage. In general, however, these laid per female. These eggs incu­ variations are shown to result from bate an average of three days. 9 First and second nymphal instars reported on only two species (Ste­ average 2! days each, after which neotarsonemus pallidus and Hem­ there is a brief period of quiesence, itarsonemus latus ). Information followed by emergence of the available from these and other adult. Complete egg to egg devel­ fragmentary studies will be used opment requires an average of elev­ as a generalized life history for the en days. Temperature variations af­ family. fect these averages considerably. Rosario and Sill (1964) report an Beer (1954) reports all tarsone­ optimum temperature for develop­ mids studied demonstrate four me­ ment and maintenance of Aceria tu­ tamorphic stages of development lipae populations at 75°F. (24°C). ( egg, larva, "pupa" and adult). The most distinguishing charac­ The use of the term "pupa" is con­ teristic of eriophyids is the pres­ sistent with the existence of a quie­ ence of only four legs. They are scent stage preceding emergence located propodosomally, both pairs of adults. Eggs are laid singly. Six­ appearing in the first nymphal in­ legged larvae emerge from the star. eggs with the three pairs of legs Parthenogenesis is common being situated in the usual adult among the eriophyids. Keifer (1938) positions of legs I, II, and III. Fol­ reports males are seldom collected lowing the larval stage, the mites in the field and in general are enter the sessile pupal stage from smaller in size than the females. which they emerge as active eight­ legged adults. Principal develop­ Tarsonemidae ments of this pupal stage are legs Geographic distribution IV and the genital apparatus. Small body size and relative scar­ Throughout all stages males are no city have limited reported obser­ more than two-thirds the size of vations of the tarsonemid mites. females. The life cycle from egg Therefore, a more complete pic­ to adult requires about two weeks. ture of the geographic distribution Reproduction by tarsonemids is of this group is not possible. Beer both parthenogenetic and sexual. (1954) reports the family as pre­ Progeny resulting from partheno­ dominantly tropical or subtropical gentic reproduction in mites usu­ in distribution with records of less ally consists of males. Garman predominant occurrence from all (1917), however, reports offspring major zoogeographical regions of of Steneotarsonemus pallidus were the world. invariably females. Parthenogene­ tic studies by workers on several Biology other tarsonemid species show the Detailed biological studies are usual male progeny.

10 DISCUSSION OF THE SPECIES

Keys and species descriptions in ranychidae is the production of this section for Tetranychidae, Eri­ webbing on the undersides of ophyidae and Tarsonemidae are leaves in which eggs are laid and the result of extensive use of pub­ which offers some protection lications by Pritchard and Baker against natural predators. Excep­ ( 1955), Keifer ( 1952 and 1965), tions to this occur for species of and Beer ( 1954) respectively. Com­ the tribes Bryobiini Reck, Petro­ plete descriptions are given only biini Reck, Hystrichonychini Prit­ for species not included in the pub­ chard and Baker, and Panonychus lications for Tetranychidae-Prit­ and Allonychus among the Tetran­ chard and Baker, ( 1955 ) ; Erio­ ychini Reck. phyidae-Keifer, (1952); and Tar­ The family Tetranychidae is sonemidae-Beer, (1954). characterized by the presence of A South Dakota county map a palpal thumb-claw complex, long, (figure 2) will aid in locating dis­ recurved stylets, tarsal claws with tributional areas of mites collected tenent hairs, a pair of eye-spots, and reported in this study. well defined peritreme, and a trans­ verse genital opening ( figure 1 and 0 3). An asterisk ( ) indicates not re­ ported in South Dakota. A taxonamic separation of the family is given below. See figures 1 and 3 for morphological charact­ Tetranychidae Donnadieu, 1875 eristics and figure 4 for setal nom­ Spider mites enclature. Spider mites are all plant feed­ Key to subfamilies of Tetranychi­ ers. Feeding is usually confined to dae undersides of leaves although high 1. Empodium with tenent hairs; populations result in dispersal to female with three pairs of anal other plant areas. They are gen­ setae and male with five pairs of erally yellowish or greenish in co­ genito-anal setae BRYOBIINAE lor although some are reddish. 1. Empodium (rarely appearing Spider mites are divided into absent) without tenent hairs, fe­ two sub-families (Bryobiinae and male with two pairs of anal setae Tetranychinae) and six tribes. The and male with four pairs of gen­ tribes of Bryobiinae are: Bryobiini, H ystrichonychini, and Petrobiini. ito-anal setae ------­ The three tribes of Tetranychinae ------TETRANYCHIN AE are: Tenuipalpoidini, Eurytetrany­ Subfamily BRYOBIINAE Berlese, chini, and T etranychini. 1913 A unique feature of most Tet­ Characteristics of the Bryobiinae u HAR01NG PERKINS CORSON MC PHERSON BROWN MARSHALL

EDMUNDS OAY

ZIEBACH WEY

BUTTE FAULK SPINIC CLARI< COOINGTON MEADE

t4YDE IHAND HAMLIN

LAWRENCE BEADLE ICINGSBUAY BROOKINGS ~ N

MOODY PENNINGTON JERAULD SANBORN !MINER LAKE

<.IJSTER MINNEHAHA

FALL RIVER

BENNETf TODD SHANNON

Figure 2. County map of South Dakota. are: none is known to produce sil­ with tenent hairs mediolaterally __ ken strands; duplex setae are lo­ ------BRYO BIINI cated at the abruptly declivate dis­ 1. Propodosoma with three pairs of tal end of the tarsus, and the prox­ dorsal setae; true claw a short but inal member of each pair is small slender pad with a pair of termi- and straight; the female has three nal tenent hairs ______2 pairs of anal setae and the male 2. ( 1) H ysterosoma with five pairs five pairs of genito-anal setae. of dorsolateral and dorsosublat­ eral setae ( with twelve pairs of Key to tribes of Bryobiinae dorsal hysterosomals) ______1. Propodosoma with four pairs of ______HYSTRICHONYCHINI~ dorsal setae; true claw long and 2. ( 1) H ysterosoma with three

~--empodium ~ t---:~;:d~::

~claws

~tenent hairs

E

Figure 3. Morphological characteristics of Tetranychidae. (A) peritreme on female;

(B) empodia1 claws and tenent hairs; (C) duplex setae on tarsus I; (D) palpal thumb-claw complex; (E) acdeagi. (From Baker, et. al., 1958.) 13 para-anals Figure 4. Dorsum (top) and venter (bottom) of hypothetical tetranychid showing setal nomenclature. (From Pritchard and Baker, 1955.) 14 pairs of dorsolateral setae ( with those of adult; lateral distance ten pairs of dorsal hysterosomals ) between bases of DC1 approxi­ ------PETRO BIINI mately four times length of seta ------praetiosa TRIBE BRYOBIINI RECK, 1952 1. Foreleg of adult less than 0.69 The tribe Bryobiini is character­ mm. long; body length less than ized by having four pairs of dorsal 0.74 mm.; lateral distance be­ propodosomals and the true claw tween bases of DC1 less than is developed as a curved hook or a 0.10 mm. Larval setae foliace­ long pad, with lateral tenent hairs. ous, like those of adult; lateral

There are twelve pairs of dorsal distance between bases of DC1 hysterosomals. approximately twice length of seta ______rubrioculus ( arborea) Key to the genera of Bryobiini 1. True claw uncinate, with one or Bryobia praetiosa Koch, 1836 several pairs of mediolateral ten- clover mite ent hairs ______Bryobia ( Figures 5 and 6) 1. True claw padlike, with two rows As noted from the above key, of ventrally directed tenent hairs 0 this species is difficult to separate ------Tetranycopsis as an adult from B. rubrioculus. Except for size (B. praetiosa is Bryobia Koch, 1836 larger), morphological differences Bryobia is characterized by sev­ are not reported as evident. eral pairs of ventrally directed ten­ Species of B. praetiosa are a ent hairs arising from a hooked common household pest during the true claw. fall and winter months. They are The genus Bryobia is represent­ reddish or reddish-brown in color ed in South Dakota by two spe­ and are not harmful in homes ex­ cies, B. praetiosa and B. rubriocu­ cept as a nuisance. In the field, lus. these mites have been reported causing serious plant feeding dam­ The key given below for separa­ age to various orchard crops (Ree­ tion of these two species is taken ves, 1963). Other hosts include al­ from Morgan and Anderson ( 1957). mond, walnut, various wild and native grasses, wheat, barley, clo­ Key to South Dakota species of ver, alfalfa, ivy, orchids, and vari_- Bryobia ous shade trees (Pritchard and Ba- l. Foreleg of adult longer than 0.69 ker, 1955). mm.; body length more than In South Dakota, this mite has 0.74 mm.; lateral distance been collected . on brome grass between bases of anterior pair (Bromus inermis), Faulk County, of dorsocentral hysterosonal se- 5/10/57; and in homes, Hughes tae (DCi) greater than 0.10 mm. County, 5/2~/54. No collections Larval setae lanceolate, unlike were made during our survey. 15 for B. arborea which is considered synonymous with B. rubrioculus and is cited below. Female - In general appear­ ance very similar to B. praetiosa as described by McGregor (1950), but smaller in size. Body length 0.551 to 0.731 mm; body width 0.348 to 0.527 mm; foreleg (excluding coxa and tarsal claws) 0.543 to 0.659 mm. Lateral distances between the bases of the paired dorso­ central hysterosomal setae: DC1, 0.047 to 0.084 mm.; DC2, 0.027 to 0.061 mm.; DC3, 0.020 to 0.044mm. Male - Not found. Species parthenogenetic. Larva - Similar to praetiosa as described by McGregor (1950),

Figure 5. Bryobia praetiosa. Dorsal as­ pect of female. (From Pritchard & Ba­ ker, 1955.)

Bryobia rubrioculus ( Scheuten, 1857 ) brown mite New record for South Dakota There is still some question among acarologists as to whether the correct name for this mite is B. arborea or B. rubrioculus ( Bak­ er and Pritchard, 1960; Eyndhov­ en, 1956; Morgan and Anderson, 1957; and Morgan, 1960). In view of the fact South Dakota specimens were identified by Baker as B. rubrioculus, that determination will be accepted for this study. Mor- Figure 6. Bryobia praetiosa. Append­ gan and Anderson ( 1957) have ages of tarsi II and IV. (From Pritchard provided the original description & Baker, 1955.) 16 but body setae foliaceous like those of the adult (not lanceo­ late to clavate as in praetiosa). Body length 0.172 to 0.193 mm.; body width 0.143 to 0.164 mm. Lateral distances between the bases of the pair­ ed dorsocentral hysterosomal setae: DC1, 0.035 to 0.053 mm.; DC2, 0.017 to 0.030 mm.; DC3, 0.013 to 0.022 mm. Egg - Spherical, slightly flat­ tened at base. Diameter: 0.136 to 0.178 mm. Holotype - Collected on De­ licious apple leaves, Summer­ land, B.C., June 13, 1955 (N. H. Anderson and H. Domini­ que). No. 6425 in the Canad­ ian National Collection, Otta­ wa. The brown mite is reported as a pest on a variety of orchard trees and other woody plants through­ out the world. This is the first re­ Figure 7. Petrobia latens. Dorsal aspect port of B. rubrioculus in South female. (From Pritchard & Baker, Dakota. 1955.)

,------true claw I I empodium

Figure 8. Petrobia latens. Tarsus I of female, with enlargement of appendages. (From Pritchard & Baker, 1955.) 17 The 1964 collections were from Petrobia Murray, 1877 apple (Pyrus malus ), Fall River Petrobia is characterized by a County, Slide Nos. 456, 457, 458, double row of ventrally directed and 459, 7 / 29/64, LDW; Hughes tenent hairs on the empodium. County, Slide Nos. 460, 461, and The genus Petrobia is repre­ 462, 7 / 23/64, LDW; and Meade sented in South Dakota by only County, Slide Nos. 463, 464, 465, one species, P. latens. 466, and 467, 8/ 19/64, LDW. Petrobia la.tens ( Muller, 1776) TRIBE PETROBIINI RECK, 1952 brown wheat mite The tribe Petrobiini differs from ( Figures 7 & 8) Bryobiini and Hystrichonychini The brown wheat mite (adult in that the second and third dorso­ female, males are not known) is lateral setae are single, rather than separated from other Petrobia spe­ paired. Thus, the hysterosoma pos­ cies in that the sacral and other sesses only five pairs of dorsolat­ dorsal hysterosomal setae are simi­ eral and dorsosublateral setae (fi­ lar in length. The dorsal setae are gure 7). The true claw consists of not set on tubercles and are short­ a small slender pad with a pair of er in length than the intervals be­ tenent hairs distally (figure 8). tween them. Key to the genera of Petrobiini P. latens is largely a pest of monocotyledonous plants such as 1. Empodium uncinate ______2 grasses, wheat, barley, sorghum, 1. Empodium without a terminal onions, gladiolus, and iris. Heavy hook, being padlike or else con- populations may cause damaging sisting of a pair of tenent hairs ____ 3 migrations to cotton, carrots, let­ 2. (1) Empodium with two rows of tuce, melons, alfalfa, burr clover, ventrally directed tenent hairs ___ _ and apple. ______Petro bia South Dakota collections of this 2. (1) Empodium with one pair mite are from winter wheat (Trit­ of mediolateral, distally directed icum aestivum), Stanley County, tenent hairs ______Schizonobia 0 5/7 /62, SDH and GM ( S. D. Ins. Surv. Rpt., 1962a) ; and alfalfa 3. (1) Hysterosoma with inner sa­ (Medicago sativa), Shannon Coun­ crals approximate and resembl­ ty, 5/4/65, PAJ. Large and damag­ ing a fourth pair of dorsocentrals ing populations of P. latens in South ------Alponobia 0 Dakota have not been reported. 3. (1) Hysterosoma with inner sa- crals more widely spaced than Subfamily TETRANYCHINAE dorsocentrals and more removed Berlese, 1913 from them than the dorsocentrals Characteristics of the Tetrany- are from each other ------chinae are: most species are pro­ ------M onoceronychus0 ducers of silken strands; duplex 18 setal location is variable, but pro­ quently requires the lateral profile ximal member is generally more of the aedeagus. Thus, representa­ strongly developed than in Bryo­ tives of both sexes are often ne­ biinae; female possesses two pairs cessary. of anal setae, and male possesses The empodium of all Tetrany­ chini is well developed. Another four pairs of genito-anal setae; the characteristic of the tribe is the true claw is reduced to a small presence of two pairs of duplex pad bearing a pair of long tenent setae on the dorsum of tarsus I hairs. and one pair on the dorsum of tarsus II. Key to the tribes of Tetranychinae l. Tarsus I dorsally w i t h two Key to the genera of Tetranychini pairs of duplex setae, the proxi­ l. Opisthosoma with two pairs of mal member of each pair short- para-anal setae ------2 er than the distal member ______2 l. Opisthosoma with a single pair of l. Tarsus I dorsally with at most a para-anals ------6 single pair of usually loosely asso­ 2. ( 1) Empodium with a simple, ciated duplex setae, the proximal clawlike dorsal member and with member usually as long as or paired proximoventral hairs ______3 longer than the distal member, or 2. (1) Empodium not clawlike and else duplex setae absent; empod- with paired proximoventral hairs ium very small or absent ______------·----- 4 0 3. (2) Empodium with a simple ------E urytetranychini "claw" nearly as long as three 2. (1) Hysterosoma with sacral se­ pairs of similar, proximoventral tae all marginal; tarsus II with hairs; tarsus I with duplex setae distal member of duplex setae adjacent near distal end of seg- a short sensory peg; propodoso- ment ______Panonychus ma reticulate dorsally ______3. (2) Empodium with "claw" much ------Tenuipalpoidini 0 shorter than the longest of the dis­ 2. (1) Hysterosoma with inner sa­ similar proximoventral hairs; tar­ crals mediodorsal; tams II with sus I with duplex setae separated distal member of duplex setae along dorsal surface of segment __ long and tapering; propodosoma ______Allonychus 0 without reticulations ______4. (2) Empodium with t~ two ------____ Tetran ychini proximoventral hairs enlarged forming two clawlike append­ TRIBE TETRANYCHINI ages, the dorsal hairs very short if present ______Schizotetranychus RECK, 1950 4. ( 2) Em podium ( excluding legs The tribe Tetranychini contains I and II of males ) comprised of most of the economically impor­ three pairs of hairs of similar tant species in the family Tetrany­ length, the proximal member of chidae. It is this group of mites for which is slightly the stronger, or which species identification fre- else with the hairs united proxim- 19 ally to form a single appendage __ 5 tarsus I usually with duplex setae 5. (4) Empodium forming a single, adjacent and placed near distal slender appendage on at least end ------Oligonychus proximal one-half ______6. ( 1) Empodium with claw like ------N eotetranychus0 dorsal member much shorter than 5. ( 4) Empodium ( excluding leg I proximoventral hairs or else rudi­ and II of male ) composed of mentary; peritreme recurved dis­ three pairs of hairs ______tally or rarely anastomosing; tar­ ------Eotetranychus sus I with duplex setae widely spaced on dorsum of segment ___ _ 6. ( 1) Empodium claw like and ------T etranychus somewhat shorter than or about as long as proximoventral hairs; Panonychus Yokoyama, 1929 peritreme usually straight distal­ The genus Panonychus is char­ ly and ending in a simple bulb; acterized by having the dorsal se-

Figure 9. Panonychus ulmi. Dorsal aspect of female. (From Pritchard & Baker 1955.) ' 20 tae borne on strong tubercles. Three pairs of proximoventral se­ tae are borne on the empodial claw. Two pairs of para-anal setae are present. In South Dakota, Panonychus is represented by only one species, P. ulmi.

Panonychus ulmi (Koch), 1836 European red mite ( Figures 9 & 10) Adult females of Panonychus ul­ mi are brick red with whitish dorsal tubercles. The outer sacrals of the hysterosoma are about two-thirds as long as the inner sacrals and longer than the clunals. Figure 10. Panonychus ulmi. (A) tarsus The European red mite is com- I of female; (B) aedeagus. (From manly a serious pest of orchards, Pritchard & Baker, 1955.) 21 Figure 11. Schizotetranychus elymus. Dorsal aspect of female. (From Pritchard & Baker, 1955.)

22 . ornamental trees and shrubs (Chapman and Lienk, 1950). This pest is common throughout much of the world, and is reported on such hosts as apple, cherry, pear, peach, plum, prune, berries, coton­ easter, pyracantha, elm, almond, walnut, mountain ash, and black locust. In South Dakota, the European red mite has been collected on apple (Pyrus malus ), Brookings County, 5/12/58; plum (Prunus domestica), Lake County. Slide Nos. 38 and 57, 8/15/64, HCS. Schizotetranychus Trig~rdh, 1915 The genus Schizotetranychus can be recognized by the presence of two claw-like appendages which are outgrowths of the ventrolater­ al pair of empodial hairs. In South Dakota, the genus is represented by only one species, Schizotetranychus elymus.

Schizotetranychus elymus McGregor, 1950 New record for South Dakota ( Figures 11, 12 & 13) Males of Schizotetranychus ely­ Figure 12. Schizotetranychus elymus. mus are characterized by having (A) tibia and tarsus I of female; (B) tib­ the aedeagus with a dorsally dir­ ia and tarsus II of female; (C) tibia and ected sigmoid portion that is about tarsus I of male; (D) tibia and tarsus II one-half the length of the shaft. of male. (From Pritchard & Baker, 1955.) Dorsal body setae of both sexes are similar in length and slightly longer than the longitudinal inter­ vals between them. In South Dakota, this mite has Little is known about the econo­ been collected on western wheat mic importance of this species. Col­ grass ( Agropyron smithii), Shan­ lections are reported for only the non County. Slide No. 434, 7 / 29/ 64, western United States. Hosts in­ LDW; and Todd County. Slide clude bent grass, Bermuda grass, Nos. 435, 436, 437, and 438, 7 / 30/ and other undetermined grasses. 64,LDW. 23 r~ :·y~r~ ·~ ~ B A

Figure 13. Schizotetranychus elymus. (A) distal segment of palpus of male; (B) distal segment of palpus of female; (C) appendages of tarsus of female; (D) aedea­ gus. (From Pritchard & Baker, 1955.)

Eotetranychus Oudemans, 1931 rounded; peritreme anastomos- ing distally ______populi Eotetranychus is characterized by the presence of the caudal pair 1. Aedeagus with a strong wave of para-anals, and having the em­ near the middle and tapering to podium (except for leg I, and a point; peritreme with simple sometimes II, of the male), consist bend distally ______matthyssei of three pairs of hairs. In South Dakota this genus is Eotetranychus populi ( Koch i, represented by two described spe­ 1838 cies ( E. populi and E. matthyssei) and one new species not yet des­ New record for South Dakota cribed. ( Figures 14 & 15) Eotetranychus populi is differ­ Key to South Dakota species of entiated from other species in this Eotetranychus, males genus by the irregular, anastomos- 1. Aedeagus with a broad curve ing enlargement of the distal end medially and with distal end of the peritreme. Another charact- 24 A r B

Figure 14. Eotetranychus populi. (A) appendages of tarsus I of male; (B) em­ podium of tarsus IV of male; (C) ap­ pendages of tarsus II of male; (D) ap­ pendages of tarsus I of female; (E) aed­ eagus. (From Pritchard & Baker, 1955.)

eristic is that the dorsal setae of the body are longer than the intervals -- between them. This mite has been reported from eastern United States, Ger­ many, and England on such hosts as poplar, willow, and aspen. Ree­ ves (1963) reported extensive damage to aspen from populations of E. populi. E In South Dakota, ornamental willow trees throughout the state suffered heavy damage from large from weeping willow (Salix baby­ populations of this mite. Large lonica), Fall River County. Slide numbers of cast skins and heavy Nos. 77, 78, 79, 80, 81, and 82, webbing were frequently encoun­ 7 / 29/ 64, LDW; Hughes County. tered on willow leaves during the Slide Nos. 101, 102, 103, 104, 105, latter half of the summer of 1964. 106, 107, 108, and 109, 7 / 23 / 64, Damage was easily discernible as LDW; Jerauld County. Slide Nos. the leaves were frequently curled 110, 111, 112, 113, 114, 115, and and chlorotic or brown. 116, 7/24/64, LDW; willow (Salix South Dakota collections were sp.), Turner County. Slide Nos. 25 83, 84, 85, 86, 87, 88, 89, 90, and 124, 125, 126, 127, and 128, 8/ 12/ 64, 91, 8/ 25/ 64, HCS; Clay County. HCS; McCook County. Slide Nos. Slide Nos. 92, 93, 94, 95, 96, 97, 98, 129,130,131,132, and 133, 8/ 15/ 64, 99, and 100, 8 126 164, HCS; Mc­ HCS; Jackson County. Slide Nos. Cook County. Slide Nos. 122, 123, 247, 248, 249, 250, 251, 252, 253, 254, and 255, 7 /30/64, LDW; gold­ en willow (S. sp.), Roberts County. Slide Nos. 117, 118, 119, 120, and 121, 8/13/ 64, LDW; Sandbar wil­ low (S. interior), Jackson County. Slide Nos. 420, 421, 422, 423, and 424, 7 /29/64, LDW; and western wheat grass (Agropyron smithii), Shannon County. Slide No. 439, 7 /29/ 64, LDW.

Eotetranychus matthyssei Reeves, 1963 New record for South Dakota (Figure 16) This species is distinctive from E. populi in that the peritreme has a simple bend at its distal end and the aedeagus is strongly curved in the middle and tapers to a point. Reeves (1963) reports this mite as a serious pest of American elm in New York. Previously reported hosts include American elm, hack­ berry, black locust, and slippery elm. The original description of E. matthyssei is given by Reeves (1963) as follows: Male - Palpus with terminal sensillum slender, about 3 times as long as wide. Peri­ treme ending distally in a sim­ ple, bent, usually I-chambered Figure 15. Eotetranychus populi. (A) tibia and tarsus I of female; (B) tibia bulb. Tibia I with 9 tactile and tarsus II of female; (C) tibia and and 3 sensory setae; tarsus I tarsus I of male; (D) tibia and tarsus II with 4 tactile and 3 sensory of male. (From Pritchard & Baker, setae proximal to the duplex 1955.) setae; empodium I tridentate, 26 B

D

C

E F

Figure 16. Eotetranychus matthyssei. (A) tibia and tarsus I of female; (B) tibia and tarsus II of female; (C) tibia and tarsus I of male; (D) tibia and tarsus II of male; (E) aedeagus; (F) terminal segment of palpus; (G) various shapes of distal end of peritreme. (From Reeves, 1963.)

the central tooth is the most as long as wide. Peritreme prominent. Tibia II with 8 ending distally in a simple, tactile setae. Aedeagus long bent, usually I-chambered and slender, strongly undulate bulb. Tibia I with 9 tactile near the center. Length of and 1 sensory setae; tarsus I body 210 microns; including with 5 tactile and 1 sensory rostrum, 232 microns ( from setae proximal to the duplex mounted specimens). setae; empodia I, 1I, III, and Female - Palpus with term­ IV composed of 3 pairs of inal sensillum 2 to 2! times hairs. Tibia II with 8 tactile 27 Figure 17. Oligonychus pratensis. Dorsal aspect of female. (From Pritchard & Bak­ er, 1955.)

28 setae. Striae just anterior to Key to South Dakota species of genital flap transverse. Length Olygonychus, males of body 290 microns; includ­ 1. Aedeagus with bent portion dir­ ing rostrum, 333 microns (from ected dorsally and bearing a ter- mounted specimens). minal knob ______pratensis In South Dakota, E. matthyssei 1. Aedeagus with bent portion di­ was collected only once. This col­ rected ventrally at an obtuse lection was on American elm (Ul­ angle and with the distal end ab- m-us americana), Roberts County. ruptly narrowed ______bicolor Slide Nos. 353, 354, and 355, 8/13/64, LDW.

Eotetranychus ( new species) A suspected new species of Eot­ etranychus is currently held by E. W. Baker pending description, and was collected from wild rose (Rosa), Sanborn County. Slide Nos. 398, 399, 400, 401, and 402, 2/6/64, LDW.

Oligonychus Berlese, 1886 The genus Oligonychus can be recognized by having the empodial claw well developed with three to six pairs of proximoventral hairs. The caudal pair of para-anal setae is absent. In South Dakota, this genus is represented by O. bicolor, 0. pra­ tensis, and one undescribed species.

Key to South Dakota species of Oligonychus, females 1. Tibia I with nine tactile setae; venter of tarsus I with two tac­ tile setae beyond first duplex; empodium with three pairs of pro- D ximoventral hairs ______pratensis 1. Tibia I with seven tactile setae; Figure 18. Oligonychus pratensis. (A) venter of tarsus I with one tac- tibia and tarsus I of female; (B) tibia and tarsus II of female; (C) tibia and tile seta beyond first duplex; em- tarsus I of male; (D) tibia and tarsus II podium, with four to six pairs of of male. (From Pritchard & Baker, proximoventral hairs ______bicolor 1955.) 29 C

Figure 19. Oligonychus pratensis. (A) empodium I of male; (B) empodium III of male; (C) empodium III of female; (D) aedeagi. (From Pritchard & Baker, 1955.)

D .,,,.-- ..,.,.....- - - ·

30 Oligonychus pratensis (Banks), 1912, Banks grass mite New record for South Dakota ( Figures 17, 18 & 19) Males of the Banks grass mite are recognized by having the distal knob of the aedeagus about twice as wide as the stem of the knob. The axis of the knob forms a right angle with the shaft. Females are characterized by having nine tac­ tile setae on tibia I. 0. pratensis is reported in various areas throughout the United States on such hosts as wheat, aspen, dates, sugar cane, para grass, smut grass, broom grass, bermuda grass, panic grass, and other grasses. In South Dakota, Banks grass mite has been collected on oats ( Avena sativa), Beadle County. Slide Nos. 426, 427, 428, 429, 430, 431, 432, and 433, 7 /8/64, HCS; wheat (Triticum aestivum), Wal­ worth County. Slide Nos. 440, 441, and 442, 6/25/64, LDW; western wheat grass (A. smithii), Hughes County. Slide Nos. 443, and 444, 7/17/64, HCS; and barley (Hord­ eum vulgare), Beadle County. Slide No. 469, 7 / 8/ 64, LDW. Economic damage from O. pra­ tensis has not been observed in South Dakota.

Oligonychus bicolor (Banks), 1894 oak mite New record for South Dakota Figure 20. Oligonychus bicolor. (A) tib­ ( Figures 20 & 21) ia and tarsus I of female; (B) tibia and tarsus II of female; (C) tibia and tarsus Of the Oligonychus species oc­ I of male; (D) tibia and tarsus II of curring in South Dakota, 0. bicolor male. (From Pritchard & Baker, 1955.) can be recognized, by the presence of seven tactile setae on tibia I and four tactile setae proximal of 31 Figure 21. podium I ofoz· ?otychu s bicolor (A) male· (C) na e; (B) empod: em­ aede~ empodium IV f mm III of 1955.r'· (From Pritc~J•;;le;Baker, (D)

D

32 the duplex setae on tarsus I. The They overwinter, or enter a female is also reddish in color. non-feeding phase, as orange This mite is recognized as a ser­ females; elsewise reproduction ious pest of oak and various orna­ is continuous throughout the mental trees throughout the eastern year. United States and in Kansas. It has The genus Tetranychus may been recorded on red oak, willow be recognized by having only oak, white oak, pine oak, beech, one pair of para-anal setae chestnut, and American elm. (the postanals being absent) In South Dakota one collection and by having the empodium has been made of this mite on oak composed of three (only two (Quercus sp.) , Lake County. Slide in T. fifiensis) pairs of proxi­ Nos. 144, 145, 146, 147, 148, 149, moventral hairs on the female, 150, 151, 152, and 153, 8/ 13/64, or on tarsi III and IV of the HCS. male, above which there is a rudimentary or small spur, Oligonychus ( new species) much shorter than the ventral­ ly directed hairs. The paired A suspected new species of Oli­ empodial hairs are all similar gonychus is currently held by E. in length and width (except in W. Baker pending description, and T. fifi ensis). was collected from crested wheat grass (A. smithii), Jerauld County. The end of the peritreme Slide Nos. 72, 73, 74, 75, and 76, always bears a long, four or 8/4/64, LDW. five chambered hook, rarely anastomosing. The duplex Tetranychus Dufour, 1832 setae on tarsus I are widely separated on the dorsum on Pritchard and Baker (1955) pro­ the tarsus, and this segment vide the following description of is long and gradually narrows Tetranychus. distally. Empodium I of the Mites belonging to the gen­ male usually consists of a pair us T etranychus feed on the un­ of short, tridigitate append­ derside of leaves of most of ages with or without a medio­ the angiospermous plants, usu­ dorsal spur, and tarsus II usu­ ally forming colonies, at least ally bears a short spur above to start with, and sometimes the paired empodial hairs. The producing a great deal of web­ aedeagus bends sharply dor­ bing. The eggs are pearly, sad, and the development of spherical, and without a dorsal the distal end is characteristic stripe. of the species. Dorsal setae of Adult females in the more the body are long and slen­ northern climates are nearly der, and they are not borne always greenish or straw-color­ on tubercles. ed, but those in tropical areas In South Dakota, T etranychus is are carmine in basic color. represented by four species, (T. mc- 33 Figure 22. Tetranychus telarius. Dorsal aspect of female. (From Pritchard & Baker, 1955.)

34 danieli, canadensis, sinhai, and tel­ T etranychus telarius ( L), 1758 arius). two-spotted spider mite ( Figures 22, 23 & 24 ) Key to South Dakota species of T etranychus Of the T etranychus species re­ ported in South Dakota, T. telarius l. Fernald with transverse ( some­ can be separated by the presence times irregularly so) striae be­ of longitudinal striae between the tween the pair of dorsocentral third pair of dorsocentral hysteroso­ hysterosomals and in the area mals and, in the females only, by caudad of these setae ( Pacificus the presence of a diamond shaped Group) ------2 striae pattern in the area caudad l. Female with longitudinal striae of the longitudinal striae. The aed­ between the third pair of dorso­ eagal knob is not more than one­ central hysterosomals and with a fifth the length of the dorsal mar­ diamond shaped pattern in the gin of the shaft. area caudad of these setae ( Tela- rius Group) ______telarius The two-spotted spider mite is world wide in distribution and is 2. ( 1) Female with transverse known to attack nearly every plant integumentory striae between in- species. For these reasons, it is the ner sacral setae ______mcdanieli most important pest species known 2. ( 1 ) Female with longtiudinal among the spider mites. In addition or irregular integumentary striae to extensive feeding damage, this between inner sacral setae ______3 mite has been recently cited as a 3. ( 2) Longitudinal pattern of striae possible plant virus disease vector between inner sacral setae slight­ (Moskovetz, 1940 and Schultz, ly irregular; neck of aedeagus 1963). about equal in length to knob; Earlier collection records in knob of aedeagus bearing acute South Dakota report the occurence angle to neck.______canadensis of T. telarius or rose (Rosa sp.), 3. ( 2) Longitudinal p a t t e r n of Brookings County, 7 /12/61 and striae between inner sacrals more from Turner County (no host re­ irregular; neck of aedeagus much cord), 7 /2/58. Field collections shorter than length of knob; knob from this study show T . telarius of aedeagus acutely angled with occurring on green beans (Phaseo­ angle to neck ______canadensis lus rulgaris), Union County. Slide Nos. 134, 135, 136, 137, 138, 139, t Males belonging to the Pacificus and Telarius 140, 141, 142, and 143, 8/26/64, Groups may be identified by reference to figures of the aedeagus, but it is exceedi ng ly LDW; soybean (Glycine sp. ), Cod­ difficult to present a key to th e shapes of the ington County. Slide Nos. 294 and simple aedeagus without considering the in­ tegumentary striae of the females. Moreover, 295, 8/ 14/ 64, LDW; and rose (Rosa females are fo und more easily than the males sp.), Hughes County. Slide No. and are nearly always present in any col­ lection. 217, 7 /30/ 64, HCS. 35 B

C

Figure 23. T etranychus telarius. (A) tibia and tarsus I of female; (B) tibia and tar­ sus II of female; (C) tibia and tarsus I of male; (D) tibia and tarsus II of male. (From Pritchard & Baker, 1955.)

36 Figure 24. T etranychus telarius Aedea­ gi. (From Pritchard & Baker, 1955.)

Figure 25. Tetranychus sinhai. (A) tibia and tarsus I o.f male; (B) tibia and tarsus II of male; (C) tibia and tanus III of male; (D) tibia and tarsus IV of male; (E) aedeagus. (From Baker, 1962.) 37 /

38 Tetranychus sinhai Baker, 1962 shorter and the knob is much New record for South Dakota more acutely angled with the ( Figures 25 & 26) neck. Male - Palpus with termi­ This description is reported from nal sensillum slender, about Baker (1962). three times as long as wide. Females of Tetranychus sin­ hai resemble those of T. cana­ Peritreme with strong hook densis (McGregor) in that the distally. Tibia I with nine tac­ integumentary striae are trans­ tile and four sensory setae; tar­ versely parallel between the sus I with three tactile and two third pair of dorsocentral hy­ sensory setae proximal to dup­ sterosomal setae and the inner lex setae; one sensory seta on sacrals, but are longitudinal level with posterior duplex set­ between the inner sacral setae. ae; empodium I with strong The longitudinal pattern, how­ dorsal spur, but smaller than ever, is more irregular than in proximoventral spurs. Tibia II canadensis, and does not ex­ with seven tactile setae; tarsus tend as far posteriorly. The II with three tactile and one aedeagus of the male has the same pattern as that of cana­ sensory setae well proximal densis but the neck is much to the duplex setae; empodium with short mediodorsal claw and three pairs of proximoven­ tral hairs. Tibia III with six tactile setae; tarsus III with a long slender sensory seta and a single proximal tactile seta, four mediodistal tactile setae, and four distal tactile setae; empodial claw lacking. Tibia IV with six tactile setae; tarsus IV with a long, slender sensory seta and two proximal ventral tactile setae, three medioven­ tral tactile setae, and four dis­ tal tactile setae; empodial claw lacking. Dorsal setae of idioso­ ma long, slender, pubescent. Aedeagus with shaft gradually Figure 26 ( above and facing page). T et­ narrowing, with short neck, ranyc h us si'nhai. (A) tibia and tarsus I and with a relatively large of female; (B) tibia and tarsus II of fe­ knob set at a strong angle male; (C) tibia and tarsus III of female; (D) tibia and tarsus IV of female; (E) with the neck, the anterior posterior dorsal portion of female show­ portion of the knob being well ing striation pattern. (From Baker, rounded. Length of body 382 1962.) microns. 39 Female - Palpus with ter- from the presence of this mite has minal sensillum stout, about been reported on barley leaves twice as long as broad. Peri- from seedling stage to just prior treme with strong hook distal- to maturity. Symptoms included ly. Tibia I with nine tactile necrosis (usually at the leaf bend), and one sensory setae; tarsus followed by yellowing and wilting I with four tactile and one from the point of feeding to the sensory setae proximal to dup- tip. The condition of necrosis was lex setae. All empodia without often accompanied by downward dorsomedian spurs. Tibia II and inward curling of the leaves. with seven tactile setae; tarsus This and other studies by these II with one long, slender sen- workers (Sinha and Wallace, 1963 sory and three tactile setae and Sinha, 1965) have placed this proximal to duplex setae. Tibia mite under suspect as a possible III with six tactile setae; tarsus vector of Agropyron mosaic virus III with a long slender sensory and an undescribed wheat virus. and single posterior tactile se- Reported hosts have included tae, with three mediodistal barley, rye, and wheat with mar- tactile setae, and four distal ginal infestations on corn and sun- tactile setae. Tibia IV with flower. seven tactile setae; tarsus IV The presence of this mite in with a long slender sensory South Dakota is the only known and a single posterior tactile report of its occurence in the Unit- setae, with four mediodistal ed States. Collections have been tactile setae, and four distal made from barley (H. vulgare), tactile setae. Hysterosoma with Spink County. Slide Nos. 154, 155, transverse striae between third 156, 157, 158, 159, 160, 161, and pair of dorsocentral and inner 162, 7 /7 /64, HCS; crested wheat sacral setae, but with irregular grass ( Agropyron cristatum), Sully longitudinal striae between in- County. Slide Nos. 165 and 166, ner sacrals. Striae lobed. Dor- 7 /24/64, HCS; crested wheat grass sal setae of idiosoma long, slen- ( A. cristatum), McPherson County. der, pubescent. Length of Slide No. 419, 7 /21 /64, LDW; bar- body 446 microns. ley (H. vulgare), Beadle County. Holotype - Male, Brandon, Slide Nos. 280, 281, 282, 283, Manitoba, July 21, 1961 (R. 7 /8/64, LDW; Brown County. N. Sinha), on barley. In the Slide Nos. 284, 285, 286, 287, 288, Canadian National Collection, and 289, 7 / 15/64, HCS; Ree wheat Ottawa. grass ( Agropyron intermedium), Since its original description McPherson County. Slide Nos. 258, from Canada in 1962, this mite 259, 260, 261, 262, 263, and 264, has been a subject of considerable 7 /21 /64, HCS; grass (genus and interest. Wallace and Sinha, (1961) species unknown ), Hughes County. reported severe infestations on bar- Slide Nos. 270, 271, and 272, ley in Manitoba, Canada. Damage 8/20/64, LDW; wheat (Triticum 40 aestivum), McPherson County. In South Dakota, this mite has Slide Nos. 256 and 269, 7 /21 / 64, been collected only on rose (Rosa HCS; Brown County. Slide No. sp. ) Butte County. Slide Nos. 257, 7 / 15/64, LDW; Grant County. 296, 297, 298, 299, 300, 301 , 302, Slide Nos. 273, 274, 275, 276, 277, and 303, 6/24 /64, LDW. 278, and 279, 7 /2/ 64, HCS; Day County. Slide No. 315, 7 / 13/64, Tetranychus canadensis ( McGreg­ HCS; Rose (Rosa sp. ), McPherson or ), 1950 four-spotted spider mite County. Slide Nos. 392, 393, 394, New record for South Dakota 395, 396, and 397, 7 /21 /64, HCS; ( Figures 27 & 29 ) and choke cherry (Prunus vir­ The four-spotted spider mite is giniana), Turner County. Slide Nos. the second species of the Pacificus 163 and 164, 8/ 25 /64, HCS. Group found in South Dakota. In addition to the Pacificus Group Tetranychus mcdanieli McGregor, features cited previously, T. cana­ 1931 Mcdaniel mite densis females bear longitudinal or New record for South Dakota irregular integumentary striae be­ ( Figures 27 & 28 ) tween the inner sacrals. The males of T. canadensis possess an aedea­ The Mcdaniel mite and four­ gus bearing a distinct distal knob spotted spider mite are the only which is about one-fourth as long species of the Pacificus Group as the dorsal margin of the shaft. found in South Dakota. Females Severe infestations following or­ of this Group are characterized by chard pest control practices have transverse striae ( sometimes irre­ been reported from Illinois ( Or­ gular) between the third pair of chard Pests, USDA, CEIR, 1961 dorsocentral hysterosomals. Trans­ and 1963 ), and Missouri ( Orchard verse striae are also present be­ Pests, USDA, CERI, 1962). tween the dorsocentral hysterosom­ Records of heavy or general in­ als and the inner sacrals. Striae be­ festation by T. canadensis have oc­ tween inner sacrals of T. mcdanieli curred in orchards in Ontario and are transverse. The peritreme of Quebec, Canada and in Missouri the Pacificus Group terminates in on peach and apple, in Illinois on a simple hook. The aedeagus of red clover, apple and peach, in T. mcdanieli is sigmoid in shape Oklahoma on tomato, beans, sweet as shown in figure 28. potato, and okra, in Massachusetts T. mcdanieli is considered a ser­ on elm, in Utah on ash, in New ious pest of fruit trees particularly Mexico on ornamentals, and in in areas of the western and north Tennessee on orchards in general. western United States. It has also Bronzing of leaves with subsequent been reported in the central and dropping has been observed in eastern United States and in Mani­ cases of heavy infestation (White, toba, Canada. Hosts have included 1964). apple, plum, prune, raspberry, and T. canadensis has been previous­ ornamentals. ly reported infesting at least 28 41 Figure 27. Pacificus Group ( Tetranychus pacificus). Dorsal aspect of female. (From Pritchard & Baker, 1955.)

42 different host plants with scattered Figure 28. T etranychus mcdanieli. Ae­ distribution in Canada and all but deagi. (From Pritchard & Baker, 1955.) the extreme western and north­ western states. In South Dakota, this mite has been observed in large numbers causing extensive damage, parti­ cularly to apple orchards in the northeastern corner of the state. South Dakota collection records for T. canadensis are lengthy and include: plum (Prunus domestica), Lincoln County. Slide Nos. 9, 10, 11, 12, 13, 14, 15, and 16, 8 /27 /64, HCS; McCook County. Slide Nos. 332, 333, 334, and 335, 8/ 12/64, HCS; Minnehaha County. Slide Nos. 1, 2, 3, 4, 5, 6, 7, and 8, 8/ 12/64, HCS; Lake County. Slide Nos. 17, 18, 19, 20, 21, 22, 23, 24, 25, and 26, 8/ 13/64, HCS; Hanson County. Slide Nos. 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, and 37, 8/ 12/64, HCS; Figure 29. Tetranychus canadensis. (A) Bon Homme County. Slide Nos. empodium I of female; (B) empodium 41, 42, 43, 44, 45, 46, 47, and 48, I of male; (C) aedeagus. (From Reeves, 1963.) 8/ 18/64, HCS; Turner County. Slide Nos. 49, 50, 51, 52, 53, 54, 55, and 56, 8/25/64, HCS; Clay 207, 208, 209, 210, and 211, 8/6/64, County. Slide Nos. 197, 198, 199, LDW; Roberts County. Slide Nos. 200, 201, 202, 203, and 204, 212, 213, and 215, LDW; choke 8/26/64, HCS; terry plum (Prunus cherry (Prunus virginiana), Turn­ d01nestica), Roberts County. Slide er County. Slide No. 379, 8/ 25 /64, Nos. 336, 337, 338, 339, 340, 341, HCS; apple (Pyrus malus), Fall and 342, 8/ 13/64, LDW; wild River County. Slide No. 265, plum (Prunus americana), San- 7 /29 /64, LDW; Hughes County, born County. Slide Nos. 205, 206, Slide Nos. 234, 235, 236, and 237, 43 PAT~LLA TROCHANTER r' ; ! I' I 'I '

44 INTERNAL Ff MALE GENITALIA TYPICAL APODEME

Figure 30 (above and facing page). Eriophyidae. Nomenclature of setae and gen­ eral body features. (From Keifer, 1952.)

7 /23/64, LDW; wild apple (P. LDW; red dutchess apple (P. ma­ sp. ), Roberts County. Slide Nos. lus), Roberts County. Slide Nos. 227, 228, 229, 230, 231, 232, and 191, 192, 193, 194, 195, ancf 196, 233, 8/13/64, LDW; dolgo crab- 8/ 13/64, LDW; wealthy apple (P . apple (P. baccata), Roberts Coun- malus), Roberts County. Slide Nos. ty. Slide Nos. 324, 325, 326, 327, 343, 344, 345, 346, 347, 348, 349, 328, 329, 330, and 331, 8/ 13/64, 350, 351, and 352, 8/13/64, LDW; LDW; whitney crab apple (P. bac- American elm (Ulmus arnericana), cata), Roberts County. Slide Nos. Roberts County. Slide Nos. 353, 178, 179, 180, 181, 182, and 183, 354, 355, 356, and 357, 8/ 13/64, 8/ 13/64, LDW; strawberry crab LDW; hollyhock (Althaea rosea), apple (P. baccata), Roberts County. Roberts County. Slide Nos. 166, Slide Nos. 358, 359, 360, 361, 362, 167, 168, and 169, 8/ 13/64, LDW; 363, 364, 365, 366, 367, and 368, green ash (Fraxinus pennsylvani- 8/13/64, LDW; N. W. greening ca), Hughes County. Slide Nos. apple (P . malus), Roberts County. 238, 239, 240, 241 , 242, 243, 244, Slide Nos. 58, 59, 60, 61, 62, 63, 64, 245, and 246, 7 /23/64, LDW; rose 184, 185, 186, 187, 188, 189, and (Rosa sp. ), Hughes County. Slide 190, 8/ 13/64, LDW; yellow deli- Nos. 218, 219, 220, 221, and 223, cious apple (P. malus), Roberts 7 /30/64, HCS; and Slide Nos. 222, County. Slide Nos. 65, 66, 67, 68, 224, 225, and 226, 7 /23/64, HCS; 69, 70, and 71, 8/13/64, LDW; Roberts County. Slide Nos. 304, 305, harlson apple (P. malus), Roberts 306, 307, 308, 309, 310, 311, 312, County. Slide Nos. 170, 171, 172, 313, and 314, 7/ 14/64, HCS; Brule 173, 174, 175, 176, and 177, 8/ 13/64, County. Slide Nos. 316, 317, 318, 45 319, 320, 321, 322, and 323, 8/5/64, with moderately long anterior LDW; and wild rose (Rosa sp.), lobe over rostrum; bands of wax Sanborn County. Slide No. 268, secreted by ridges; habit-living 8/6/64, LDW. on leaf surfaces or in surface cren- ulations, a rust mite ______Eriophyidae Nalepa, 1898 ------Abacarus hystrix eriophyid mites 1. Abdomen approximately circular in cross section, ridge if present, Baker and Wharton (1952) pro­ weaker than above ______2 vide the following description of 2. (1) Moderate lobe over rostrum; eriophyids. a short line forming an arc in The eriphyids are minute, front of each dorsal tubercle; worm like mites whose propo­ weak dorsal longitudinal abdom­ dosoma is shield like and has inal ridge; microtubercles on distincitive, specific patterns. ring margins; habit - a rust mite __ The hysterosoma is elongated ------Aculus dubius and annulate. These mites do 2. (1) Abdomen circular in cross not possess a respiratory sys­ section; no arc in front of dorsal tem. Two pairs of anterior legs tubercles ------3 are present in all stages and 3. (2) Small shield lobe over ros­ all tarsi have rayed claws. The trum base; microtubercles as genitalia are situated on the beads on ring margins; body cov­ anterior, ventral portion of the ered with dusty wax; habit-liv­ body just behind the legs and ing in leaf crenulations, a rust mite ______the genital plate is a trans­ Aculus mckenziei verse rather than a longitudi­ 3. (2) Shield lobe over rostrum nal slit. Palpi are short and negligible; microtubercles point­ simple. The chelicerae are ed, set ahead of ring margins, in short-like for piercing. The part projecting over margins; no anal opening is on the poster­ wax; habit-living under cover in ior of the body. These mites curled leaves or at leave bases ___ _ are either free living on plants ------Aceria tulipae or gall makers. Taxonomic characters used in Abacarus hystrix ( N al. ) , 1944 identification of the Eriophyidae grain rust mite are shown in figure 30. The following description of the Keifer (1965) has provided the grain rust mite is provided from key below for identification of eri­ Keifer (1944). ophyed species known to occur in Female 180-200 microns South Dakota. long, 35-40 microns wide, 45 microns thick, whitish; in life Key to known adult species of with a central longitudinal Eriophyidae in South Dakota stripe of wax, enclosed by a 1. Strong middorsal longitudinal ab­ lateral band on each side. Ros­ dominal ridge present; shield trum 30 microns long, antapi- 46 ~D

Figure 31. Abacanus hystrix. (A) dorsal view; (B) feather claw; (C) lateral view; (D) internal female genitalia; (E) lateral integeument structure; (F) female geni­ talia and coxae from below; (G) left leg. (From Keifer, 1952.)

47 cal seta 8.5 microns long. the northern hemisphere and is Shield 50 microns long, 35 mi­ considered of economic importance crons wide; anterior lobe nar­ in several areas. rowed above, a spine below; In South Dakota this mite has shield with a central ridge, lat­ been collected on alfalfa (Medi­ erally granulate; dorsal tuber­ cago sativa), county unknown, cles 23.5 microns apart, on rear margin; dorsal setae 20 6/7 /56; orchard grass (Dactylis microns long, projecting cau­ glomerata), Jerauld County dad. Forelegs 36 microns long, 4/ 26/56; blue grama grass (Boute­ tibia 8.5 microns long, tarsus loua gracilis), Perkins County. Slide 8 microns long; claw 9 microns Nos. 45, 46, and 47, 7 /16/64, LDW; long, curved tapering; feather­ winter wheat (Triticum aestivum), claw 8 rayed. Hindlegs 35 mi­ Roberts County. Slide Nos. 40, 41, crons long, tibia 7 microns 42, 43, and 44, 7 /14/64, HCS; long, tarsus 7 microns long, grass ( species unknown), Hand claw 7.5 microns long, coxae County. Slide Nos. 28, 29, 30, 31, with strong sternal line. Ab­ 32, 33, 34, 35, 36, 37, 38, and 39, domen with sternites micro­ tuberculate, the microtubercles 7 /28/64, HCS; prairie cordgrass suppressed or absent on ter­ (Spartina pectinata), Union Coun­ gites; the central longitudinal ty. Slide Nos. 79, 80, 81, 82, and wax-bearing ridge ending in 83, 8/ 26/64, LDW; Hanson County. the dorsal trough on about the Slide Nos. 73 and 74, 8/ 12/64, 46th tergite, supralateral wax­ LDW; barley (Hordum vulgare), bearing ridges extending far­ Brown County. Slide Nos. 57, 58, ther caudad; tergites about as 59, 60, and 61 , 7 /15/64, LDW; numerous as sternites; sternites crested wheat grass ( Agropyron 60-65. Lateral seta 35 microns cristaturn), Sully County. Slide long, on about sternite 6; first Nos. 53, 54, 55, and 56, 7 /29/64, ventral 36 microns long, on HCS; Potter County. Slide Nos. about sternite 21; second ven­ 62 and 63, 7 /28/64, HCS; and tral 23 microns long, on about western wheatgrass (A. smithii), sternite 38; third ventral 27 mi­ Hand County. Slide Nos. 48, 49, crons long, on about 4 from 50, 51, and 52, 7/ 17/64, LDW; rear; accessory seta present. Sully County. Slide Nos. 66 and Female genitalia deep basin­ 67, 7/17/64, LDW. shaped externally, 21 microns wide, 16 microns long cover­ Aculus ( P) dubius flap with about 12 furrows, set New record for South Dakota 40 microns long. Keifer (1965) reports this mite Male 170-190 microns long, as a relatively new species, for 40 microns wide, 35-40 mic- which he has not yet published an rons thick. original description. According to This mite is widely distributed Keifer, the only previous record of on perennial grasses throughout this mite is from Idaho and in 48 Europe. The key to this species numerous; microtubercles ac­ has been previously cited. There is uminate; sternites about 65 in some question on the genus pend­ number. Lateral setae 30 mic­ ing further investigation. rons long, on about sternite In South Dakota, this mite was 23; second ventral 26 microns collected only once on western long on about sternite 39; third wheat grass ( A. smithii ), Bennett ventral about 25 microns long, County. Slide Nos. 71 and 72, on about sternite 5 from rear; 7/29/64, LDW. accessory seta present. Female genitalia 23 microns wide, 17.5 microns long, coverflap with Ac-ulus mckenziei (Keifer) 1944 about 12 long furrows, seta New record for South Dakota 25 microns long. ( Figure 32) Male 150-170 microns long, The original description of A. 35-40 microns thick. mckenziei is provided from Keifer The only host in South Dakota (1944). on which this mite has been col­ Female 170-210 microns lected is western wheat grass ( Ag­ long, 40-59 microns thick, ropyron smithii), Corson County. wormlike, white; in life cover­ Slide Nos. 18, 19, 20, 21, 22, 23, ed with white powdery wax. 24, 25, 26, and 27, 7/17/64, LDW; Rostrum 35 microns long, large Potter County. Slide Nos. 15, 16, downcurved, apical seta 12 and 17, 7/ 17/64, LDW; Hyde microns long. Shield 46 mic­ County. Slide Nos. 7, 8, 9, 10, 11, rons long, 40 microns wide, 12, 13, and 14, 7/17/64, LDW; the anterior lobe narrow and Tripp County. Slide Nos. 68 and pointed; design of longitudinal 69, 7 /31/64, LDW; Lyman County. lines curved to the rear; gran­ Slide Nos. 64 and 65, 7 /23/64, ules to the rear and sides. LDW. Dorsal tubercles 35 microns apart, on rear shield margin; Aceria t-ulipae ( K.) 1944 dorsal setae 43 microns long, wheat curl mite projecting caudad. Forelegs 36 ( Figure 33) microns long, tibia 9 microns long, tarsus 10 microns long; Keifer (1938) provides the fol­ claw 11 microns long, curved, lowmg original description of A. tapering; featherclaw 7-rayed. tulipae. Hindlegs 33 microns long, tib­ Female spindle-form a little ia 6 microns long, tarsus 8.5 curved, whitish, 210-250 mic­ microns long, claw 12 microns rons long, 50 to 65 microns long. Anterior coxae broadly wide. Rostrum 28 microns contiguous; setae 1 opposite long, gently bent down. Shield anterior point of junction. Ab­ but little curved above, sub­ domen completely microtuber­ triangular, slightly overlying culate and Eriophyiform, with the rostrum base, 39 microns the sternites slightly more long by 36 microns wide; de- 49 C E

Figure 32. Aculus mckenziei. (A) dorsal view; (B)dorsal view of shield; (C) fea­ ther claw; (D) lateral integument structure; (E) internal female genitalia; (F) fe­ male genitalia and coxae from below; (G) left leg. (From Keifer, 1952.) 50 D

H Figure 33. Aceria tulipae. (A) lateral view; (B) ventral view; (C) dorsal view of shield; (D) lateral integument structure; (E) lateral view of.posterior section; (F & I) ventral view of female genitalia; (G) feather claw; (H) tarsus; (J) left legs. (From Keifer, 1938.) 51 sign clear and in disc basically A. tulipae is a well known vec­ of five diverging lines, the tor of wheat streak mosaic virus. shield sides with curved lines This disease has been especially and band of granulations serious in the central Grain Belt above edge; dorsal tubercles States and Canada. Extensive re­ moderate in size on rear mar­ search has been conducted on the gin, 23 microns apart, the se­ wheat curl mite and its role as a tae projecting backward over virus vector. (Slykhuis, 1959, 1961, 60 microns long. Legs moder­ del Rosario, et. al, 1964, and Conn­ ately long and slender. Fore­ in, 1956). legs 40.5 microns long, In South Dakota, A. tulipae has patella 8 microns long, tibia 9 known distribution in virtually all microns long; patellar seta 28.5 winter wheat growing areas, (West microns long; claw ratfier River Counties). This pest has also strongly downcurved, slender, about 10 microns long; fea­ been reported in counties along therclaw 7-rayed. Hindleg 36 the eastern edge of the Missouri microns long, patella 8 mic­ River ( S. D. Ins. Surv. Rpt., 1962b rons long, tibia 8 microns long, and 1964) . patellar seta 14 microns long, Confirmation is awaited from claw 11 microns long. Anterior Keifer on possible A. tulipae col­ coxae touching, sternal ridge lected during the 1964 survey. forked; coxae and suboral plate minutely granulate; seta Abacarus ( new species ) of second coxa 40 microns long. Abdomen with 85 to 90 Among the eriophyids collected in rings, some ventrad reduction South Dakota is a new species in number; rings about 2 mic­ ( Keifer, 1965), from Sporobolus rons wide, the microtubercles for which we have no specific des­ partly resting on rear edge of cription at this time, but which is each ring; last 5 or 6 rings in the genus Abacarus and is close­ with microstriations. Lateral ly related to A. hystrix. seta on about ring 10, above This mite was collected only on genital seta, 35.5 microns long. alkali sacatan (Sporobolus airo­ First ventral seta about ring 27, ides ), Sanborn County. Slide Nos. and 54 microns long. Second 1, 2, 3, 4, 5, and 6, 8/6/64, HCS. ventral 35 or more microns long These mites are presently in the and on ring 50. Third ventral possession of H. H. Keifer. 31 microns long, 5 or 6 from rear. Caudal seta about 80 Tarsonemidae Kramer, 1877 microns long; accessory seta ( Figure 34) 4.5 microns long. Female gen­ italia 24 microns wide, 17.5 The tarsonemid mites are treat- , microns long, subcordate, cov­ ed in exhaustive detail by Beer erflap longitudinally furrowed, (1954) from which the following seta 12 microns long. partial description is extracted. 52 ------···· · cheliceral sheath

apodeme Ill

-·-·····---- apodeme IV

posterior median apodeme

Figure 34. Tarsonemidae. Taxonomic structures. (From Beer, 1954.)

Tarsonemid mites are very ferent. In the female the usual small, ranging in length from condition is an ovoid body one tenth to one third of a shape with the anterior pairs millimeter. The integument is of legs separated from the pos­ relatively hard in the mature terior pairs by a distinct inter­ forms and has a shiny surface. val and the dorsum of the body The body is rather sparsely convex. A group of species in beset with setae as are th0 the genus Steneotarsonemus hind appendages. The anteri­ has apparently undergone or pairs of legs, especially much modification in respect their terminal segments, are to general body contour, no more densely clothed with se­ doubt related to the adapta­ tae and often are equipped tion for their particular habi­ with specialized sensory setae tats. Females of these species of various configurations and are quite elongate, with the sizes. anterior and posterior pairs of Pronounced sexual dimor­ legs widely separated. In ad­ phism is characteristic. The dition, the mites of both sexes males are not only much small­ are dorsoventrally depressed er in size than females of the which is indeed a configura­ same species, but the general tion quite suitable for their body contour is markedly dif- activities in the confined 53 spaces between the sheaths coxae IV and the portion be­ and stems of the grasslike hind the legs. Names applied hosts. to these two regions of the The body of a tarsonemid hysterosoma are the metapo­ mite is divided into three well­ dosoma and the opisthosoma, defined portions and may be for tl).e anterior and posterior further dividied by the use of portions respectively. established terminology as de­ The mouth parts consist of fined below. The mouthparts stout, paired palpi of indis­ are contained in a distinct tinct segmentation inserted on capsular head called the cap­ the apical portion of the cap­ itulum. The remainder of the itulum, and slender, styliform, body comprises the idiosoma paired chelicerae, the bases of which is transected by a de­ which are inserted just medial­ finite and distinct suture, call­ ly to the bases of the palpi. Sit­ ed the main body suture, be­ uated medially and internally tween the anterior and poste­ in the capitulum are paired, rior pairs of legs. The unseg­ tubelike structures which are mented area anterior to the referred to in this paper as main body suture is called the cheliceral sheaths. propodosoma and the portion Tarsonemids are character­ of the idiosoma behind the ized by the pronounced devel­ main body suture is the hys­ opment of apodemes on the terosoma. The propodosoma is ventral portion of the body. a single, more or less contin­ The apodemes have been de­ uous body region, which in signated by the present writer some species has the dorsum as follows: apodemes I, which prolonged anteriorly forming have their anterolateral termi­ what is called a cephalothor­ na in the region of the anteri­ acic or rostral shield which is or margins of coxae I; apode­ sometimes separated from the mes II, which have their an­ remainder of the dorsal pro­ terolateral termina in the re­ podosoma by a suture. Such a gion of the anterior margins prolongation or forward exten­ of coxae II; anterior median sion of the dorsum of the pro­ apodeme, which is medial in podosoma, which occurs in position on the propodosoma; many families of mites, has transverse apodeme, which is also been designated by var­ associated with the main body ious authors as the cephalo­ suture; apodemes III, which thoracic hood or rostral hood. terminate posterolaterally in The hysterosoma may be furth­ the region of the anterior ex­ er divided into anterior and tremities of coxae III; apode­ posterior portions or that por­ mes IV, which terminate pos­ tion from the main body su­ teriorly near coxae IV; poste­ ture to the hind margins of rior median apodeme which 54 occupies a median longitudi­ the third projecting caudally nal position on the metapodo­ from the posteromesal mar­ soma. gin of the disc. However, in The males are equipped some species there may be caudally with a rather unique four anal apodemes, two pro­ structure which Ewing and jecting from the anterior mar­ other authors refer to as the gin of the disc and two from genital papilla. The papilla is the posterior margin, and one situated terminally on the op­ species has one apodeme pro­ isthosoma in living specimens jecting forward from the disc but in microslide preparations and two projecting caudad. it usually tilts to appear in a Females are characterized dorsal position with the dorsal by the possession of special­ margin thus appearing as the ized organs located dorsolat­ anterior margin and the ven­ erally between coxae I and tral margin projecting caudad II. These organs, which vary beyond the apex of the op­ somewhat in size and shape isthosoma. It contains within are of uncertain function and its clearly defined limits the have been called clavate sense paired, styliform aedeagi as organs or pseudostigmatic or­ well as other accessory genital gans by various workers. The organs and appendages, the term pseudostigmatic organs exact identity of which are as is used by the present writer yet unknown. Another struc­ although the applicability of ture, referred to in this paper this name is questionable. Pro­ as the anal plate is often bably these paired structures quite conspicuous in slide­ are highly modified sensilla mounted specimens. Its posi­ trichodea and are more pro­ tion in living males is subter­ perly referred to as special­ minal on the ventral opistho­ ized sense organs, since they soma just anterior to the ven­ seem to have no relationship tral margin of the genital pap­ to the tracheal system. illa, although in microslide Classification of the family mounts this normal position is T arsonemidae has been based not often apparent. The plate largely upon characters of the is lacking in clearly defined hind pair of legs of the males, lateral limitations, the most this being a logical method of conspicuous portion of the separation because of the vari­ structure being a central disc ability of these appendages. or aperature from which fin­ gerlike apodemes radiate. The Key to the Genera of the Family usual number of anal apode­ T arsonemidae mes is three, two of which extend anterolaterally for a 1. Palpi of both sexes prolonged an­ short distance from the antero­ teriorly forming an elongate beak lateral margins of the disc and ______Rhynchotarsonemus0 55 1. Palpi of both sexes projecting gins highly modified to form a slightly beyond apex of capitu­ flangelike process, never with lum but never forming an elon­ a spurlike projection; the cap­ gate beak ------2 itulum is usually subcircular, 2. ( 1) Males without claws, em­ often as broad as or broader podia or knoblike arolia on tips of than long, never with extreme­ legs IV ______Xenotarsonemus 0 ly long palpi. Females never 2. (1) Males with legs IV termina­ with a conspicuous transverse ting in a claw or knoblike pretar­ apodeme near main body su­ ture; body often elongate, with sal element ------3 anterior pairs of legs widely 3. ( 2) Males with body laterally separated from posterior pairs; compressed; tibia and tarsus or capitulum, as in male, usually tibiotarsus IV slender, elongate, as broad as or broader than more than three times as long as long, first pair of ventral pro­ basal width of tibia or tibiotarsus __ podosomal setae usually in 0 ------H emitarsonemus front of apodemes I; tracheae 3. (2) Males with body dorsoven­ often with large conspicuous trally depressed; tibia and tarsus bilobed pouches or atria situat­ or tibiotarsus IV at most two and ed medially between legs I one-half times as long as basal and II. The members of this width of tibia or tibiotarsus ______4 genus are all phytophagous 4. (3) Males with large, flangelike (Beer, 1954). expansion on inner margin of fe­ mur IV or if absent then fourth Steneotarsonemus hyaleos dorsal propodosornal seta in lin­ Beer, ( 1954) ear arrangements with setae of New record for South Dakota three preceding pairs or capitul- (Figure 35) um broader than long ______Steneotarsonemus This is the only tarsonemid spe­ cies collected to date in South Da­ 4. ( 3) Males with inner flange on kota. The male can be recognized femur IV absent or greatly reduc­ from other Steneotarsonemus spe­ ed in size; fourth dorsal propodo­ cies by having the inner margin of somal seta always laterad from femur IV with a flangelike expan­ third seta or capitulum longer sion, a propodosoma with four pairs than broad ______Tarsonemus 0 of dorsal setae (the fourth pair being longer than the other three), Genus Steneotarsonemus Beer and coxae III densely punctuate ( 1954) over most of their surfaces. The males with one excep­ Collections of this mite in South tion all have the dorsal pro­ Dakota were scattered and few. podosomal setae in linear ar­ They include: rough dropseed rangement, the usual number (Sporobolus asper), Meade County. being four pairs, femora IV Slide Nos. 445 and 446, 8/ 19/64, usually have the inner mar- LDW; big blue stem grass (Andro- 56 B

pogon gerardii), Meade County. Slide No. 447, 8/19/64, LDW; western wheat grass ( Agropyron smithii), Potter County. Slide No. 448, 7/ 17/64, LDW; and Fall Riv­ er County. Slide Nos. 449 and 450, 6/2~/64, LDW; wheat (Triticum aestivum), Brown County. Slide Nos. 451 and 452, 7/ 15/64, LDW; and blue grama grass (Bouteloua Figure 35. Steneotarsonemus hyaleos. gracilis), Lyman County. Slide (A) dorsal and ventral aspects of male; Nos. 453 and 454, 7 / 24/64, LDW; (B) hind leg; (C) tibiotarsal segment of and Stanley County. Slide No. 455, leg I of female. (From Beer, 1954.) 7 /23 /64, LDW. Miscellaneous Mite Collections hers of the family Phytoseiidae. A few instances were noted of Although no attempt was made to mites found in association with the determine species, the family is usual plant feeders other than generally recognized as beneficial those previously cited in this study. These collections are listed below. due to the presence of predaceous species. Reference is made to Baker and Wharton (1952) for general in­ South Dakota collection records include mesotigmatids from wild formation on these mite groups. plum (Prunus americana), Roberts M esostigmata County. Slide Nos. 214 and 216, The mesostigmatids collected 8/ 13/64, LDW; plum (P. domes­ during this survey were all mem- tica), McCook County. Slide Nos. 57 478 and 479, 8/ 12/64, HCS; holly­ family are represented by the gen­ hock (Althaea rosea), Roberts us Pronematus on prairie cordgrass County. Slide No. 489, 8/ 13/64, (Spartina pectinata), Hutchinson LDW; choke cherry (Prunus vir County. Slide Nos. 266 and 267, giniana), Turner County. Slide 8/ 20/64, HCS; wild rose (Rosa Nos. 380, 381, and 382, 8/25 /64, sp. ), Faulk County. Slide Nos. HCS; apple (Pyrus malus), Fall 383, 384, 385, and 386, 7 /22/64, River County. Slide Nos. 371, 372, LDW; and rose bush (Rosa sp.), 373, 374, 375, 376, 377, and 378, Mc.Pherson County. Slide No. 468, 7 / 29/64, LDW; Roberts County. 7 /21 /64, HCS. Slide Nos. 481, 482, and 484, 8/ 13./ Stigmaeidae. The only collection 64, LDW; Slide No. 485, 8/ 14/64, from this family was Agistemus LDW; American elm (Ulmus -fleschneri on apple (Pyrus malus), americana), Roberts County. Slide Brookings County. Slide Nos. 403, No. 483, 8/ 13/64, LDW; oats 404, 405, 406, 407, 408, and 409, (Avena sativa), Hand County. 9/20/64, LDW. Slide No. 486, 7 /7 /64, HCS; Deuel Erythaeidae. In this family only County. Slide No. 487, 7 /1/64, one specimen (Balaustium sp.) HCS; and big blue stem grass ( An­ was collected on whitney crab dropogon gerardii), Meade County. apple (Pyrus baccata), Roberts Slide No. 488, 8/ 19/64, LDW. County. Slide No. 480, 8/ 13/64, LDW. Trombidiformes In addition to the trombidifor­ Sarcoptif ormes mes previously covered, a few less The sarcoptiformes collected dur­ important species were also col­ ing this survey were of undetermin­ lected during 1964. These scattered ed nymphal species of the Oribatei collections include representatives Group. They were from a single of three families: Tydeidae, Stig­ collection on wheat (Triticum ae­ maeidae and Erythraeidae. stivum), Brown County. Slide Nos. Tydeidae. Collections from this 367 and 370, 7 /15/64, HCS.

58 LITERATURE CITED

Baker, E.W. 1962. Tetranychus sin­ Garman, P. 1917. Tarsonemus pal­ hai, a new species of mite from lidus Banks, a pest of geraniums. grasses ( Acarina: Tetranychi­ Md. Agric. Exp. Sta. Bull., 208: dae) . Canad. Entomol. 94 ( 9) : 327-342. 956-966. Keifer, H. H. 1938. Eriophyid Baker, E. W., J. H. Camin, F. studies. Bull. Dept. Agric. State Cunliffe, T. A. Woolley, and of California. 27 ( 2): 181-206. C. E. Yunker. 1958. Guide to Keifer, H. H. 1944. Eriophyid the Families of Mites. Institute studies XIV. Bull. Dept. Agric. Acarology, No. 3, Univ. Md. State of California. 33 ( 1) : 18-64. Baker, E. W., and A. E. Pritchard. Keifer, H. H. 1952. The Eriophyid 1960. The tetranychoid mites of mites of California ( Acarina: Africa. Hilgardia. 29(11): 455- 574. Eriophyidae). Bull. Calif. Ins. Baker, E. W. and G. W. Wharton. Surv. Vol. 2, No. 1. 1952. An Introduction to Acar­ Keifer, H. H. 1965. Personal com­ ology. MacMillan Co., New York. munication and correspondence. Beer, R. E. 1954. A revision of the McGregor, E. A. 1950. Mites of the tarsonemidae of the western family Tetranychidae. Amer. hemisphere. Univ. Kansas Sci. Midland Nat. 44:257-420. Bull. 36 (16): 1091-1387. Morgan, C. V. G. 1960. Bryobia Chapman, P. J. and S. E. Lienk. agropyra, a new species allied 1950. Orchard mite control ex­ to curiosa, from British Columbia periments in western New York. (Acarina: Tetranychidae). Can­ J. Econ. Entomol. 43( 3): 309- ad. Entomol. 92 ( 10) : 780-786. 314. Morgan, C. V. G. and N. H. Ander­ Connin, R. V. 1956. The host range son. 1958. Techniques for biologi­ of the wheat curl mite, vector of cal studies of tetranychid mites, wheat streak mosaic. J. Econ. especially Brybia arborea M. and Entomol. 49(1): 1-4. A. and B. praetiosa. Koch. Canad. Eyndhoven, G. L. Van. 1956. Mod­ Entomol. 90: 212-215. ern views on the systematics of Morgan, C. V. G. and N. H. An­ t h e genus Bryobia. Entomol. derson. 1957. Bryobia arborea Ber. 16: 20-21. n. sp. and morphological char-

59 acters distinguishing it from B. Sinha, R. N. and H. A.H. Wallace. praetiosa Koch ( Acarina: Tetran­ 1963. T etranychus sinhai Baker ychidae) . C a n a d. Entomol. (Acarina: Tetranychidae) a new 89 (11): 485-490. pest of cereals-varietal reaction Moskovetz, S. N. 1940. Plant virus of barley. Canad. Entomol. 95 diseases and their control. Tran. (6): 588-596. Con£. Plant Virus Disease. Mos­ Sinha, R. N. 1965. Personal corres­ cow 4-711. Moscow, Inst. Mik­ pondence. robiol. Izd. Akad. Nauk. U.S.S.R. Slykhuis, J. T. 1955. Aceria tulipae 1941. Keifer ( Acarina: Eriophyidae) Orchard pests. USDA Coop. Econ. in relation to the spread of wheat Ins. Report (1961), 11(25): 532. streak mosaic. Phytopath. 45: Orchard pests. USDA Coop. Econ. 111-128. Ins. Report ( 1962), 12 ( 27) : Slykhuis, J. T. 1959. Current status 725. of mite - transmitted plant vir­ Orchard pests. USDA Coop. Econ. uses. Proc. Entomol. Soc. Ont. Ins. Report (1963), 13(10): 202. 90 (1959)-1960. Pritchard, A. E. and E. W . Baker. Slykhuis, J. T. 1961. Streak mosaic. 1955. A Revision of the -Spider Canad. Plant Dis. Surv. 41: 329. Mite Family Tetranychidae, Vol. South Dakota Ins. Surv. Report 2. Pac. Coast Entomol. Soc. San ( 1962a), No. 8. Francisco 18, Calif. South Dakota Ins. Surv. Report Reeves, R. M1 1963. Tetranychidae (1962b), No. 11. infesting woody plants in New South Dakota Ins. Surv. Report York state, and a life history (1964), No. 6. study of the elm spider mite Staples, R. and W. B. Allington. Eotetranychus matthyssei n. sp. 1956. Streak mosaic of wheat in Mem. No. 380. Cornell Univ. Nebraska and its control. Univ. Agric. Expt. Sta. N. Y. St. Coll. Nebr. Res. Bull. 178: 1-41. Agric. Wallace, H. A. H., and R. N. Sinha. Rosario, M. S. E. del and W. H. 1961. Note on a new mite dis­ Sill, Jr. 1964. Additional biolog­ ease of barley and other cereals. cial and ecological characteristics Canad. J. Plant Sci. 41: 871. of Aceria tuli'pae ( Acarina: tet­ White, L. D. 1964. Laboratory ranychidae). J. Econ. Entomol. studies on the effects of temper­ 57 (6): 893-896. ature, relative humidity, and Schulz, J. T. 1963. Tetranychus host variations of T etranychus telarius ( L. ) , new vector of vir­ canadensis (McGregor) in Utah. us Y. Plant Dis. Rptr. 47 ( 7): unpublished Ph.D. dissertation, 594-596. Ut. St. Univ.

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