-. ~ III 1~2.5 I.:.;i 12.8 1.0 w ....., 1.0 W ~ ~II~ w I~ wW w 2.2 w .2 &.:: Ii£ &.:: ~ &:.: III :;: ~ ~ ~ ... ... 1.1 ....... 1.1 w.... 111111. 25 111111.4. 111111.6 111111.25 111111.4 111111.6 . / MICROCOPY RESOLUTION TEST CHART MICROCOPY RESOLUTION TEST CHART NAllONAl BUREAU Of SlANDARDS-J9&3-A NAllOliAl BUREAU Of STANDARDS-J963-A tL .)-;' G3) Ur3-! TB/1581/9/197a 1/ \ IMPACT OF PERILLIJS BIOCULATUS ON THE COLORADO POTATO BEETLE AND PLANT DAMAGE ~ .-C~$ ;5 ~~ CD ;-­ :~f: m r'~ ,';2 ....­ ~,;:::J ;~ en .....-! c;,u ~ :> c:u C) b.O r= Z <::::::t: en c,:) --' ~. UNITED STATES TECHNICAL PREPARED BY fUJ) DEPARTMENT OF BULLETIN SCIENCE AND Q~ AGRICULTURE NUMBER 1581 EDUCATION ADMINISTRATION On January 24, 1978, four USDA agencies-Agricultural Research Service (ARC), Cooperative State Research Service (CSRS), Extension Service (ES), and the National Agricultural Library (NAL)-merged to become a new or­ ganization, the Science and Education Administration (SEA), U.S. Depart­ ment of Agriculture. TI!M~ publication was prepared by the Science and Education Administration's Federal Research staff, which was formerly the AgTicultural Research Service. Trade names and the names of commercial companies are used in this publi­ cation solely to provide specific information. Mention ofa trade name or manu­ facturer does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture nor an endorsement by the Department over other products not mentioned. Washington, D,C. Issued September 1978 ABSTRACT George Tamaki and B. A. Butt. Impact of PerUlus Bioculatus on the Colorado Potato Beetle and Plant Damage. U.S. Department ofAgriculture, Technical Bulletin 1581, 11 pp. 1978 The potential impact of Perilills bioculatus, a pentatomid predator, on the Colo!:ado potato beetle, Leptinotarsa decemlineata, was evaluated by studying the biology, constructing life tables, and determining the feeding potential of different life stages of the prE.1dator on the eggs and larval stages of the de­ foliator. At average temperatures of24° C, the developmental time ofthe egg of P. bioclllatlls was about 8 days and for the nymphal stage, about 17 days. Predator nymphs consumed up to 39 eggs or 0.6 of a large larva of L. decem­ lineata per day. The potential replacement rate was 46 daughters per genera­ tion. The population ofP. bl:oculatus is able to double its size in 8Vz days, and the generation time is 47 days. In laboratory studies, L. decemlineata on potato foliage ,consumed 2,710 mm2 of potato leafarea during its larval development at 24° ± 7° C. The fourth stage of the beetle consumed an average of 538 mm2 and the adults, 687 mm2 of foilage per day. Field census of all stages of the beetle on potatoes and the total leaf areas of potato plants were measured at different times of the year. For instance, the field population of an average of 26.4 larvae and adult beetles per plant on July 14 consumed 14,037 mm2 of leaf area per plant and can com­ pletely defoliate a medium-size pl.ant in 11 days. Given the number and life stages of the predators and defoliators, we pre­ dicted the amount of predation and defoliation. Knowing the size of the potato plants, we predicted the percentage of defoliation resulting from the predator­ prey-plant interaction. Moreover, knowing the percentage of defoliation of a plant, we estimated the yield loss. KEYWORDS: Perillus bioculatus, Colora-:io potato beetle, Leptinotarsa de­ cemlineata, pest management, biological control, crop damage, predators, potato pest, modeling, twospotted stink bug, Solanum tuberosum. CONTENTS Page Introduction ........................................................ 1 Predator-Perillus bioculatus . 1 Materials and methods ............................................ 1 Results and discussion .. 2 Pest-Leptinotarsa decemlineata . 5 Materia.ls and methods ............................................ 5 Results and discussion ................... , . .. 7 Plant-Solanum tuberosum .......................................... 8 Materials and methods ............................................ 8 Results and discussion . 8 Predator-prey-plant-yield interaction ................................. 8 Predator-prey. 8 Predator-prey-fo1iage .............................................. 9 Predator-prey-plant. 9 Predator-prey-yield . .. 9 Literature cited ..................................................... 11 IMPACT OF PERILLUS BIOCULATUS ON THE COLORADO POTATO BEETLE AND PLANT DAMAGE By GEORGE TAMAKI and B.A. BuTI', research entomologists 1 INTRODUCTION In North America, Gibson et al. (7)2 intensively biology of a pentatomid predator, the twospotted studied the Colorado potato beetle, Leptinotarsa stink bug, Perillus bioculatus (Fabricius), and decemlineata (Say); however, for the last 50 years, found it to be an important predator of the L. de­ most of the literature on L. decerrtlineata is from cemlineata. Since the late 1920's, many attempts research done in Europe, and much of the very have been made to establish and to study this recent published work sterns from eastern Euro­ predator in France (24), West Germany (5), Po­ pean countries (10). This indicates the Colorado land W5), Czechoslovakia (11), Hungary (12), potato beetle is a more serious pest in Europe Russia (17), and Italy (23). In 1967, Szmidt and than in North America, probably because L. de­Wegorek (20) reported that when P. bioculatus cemlineata is native to North America and was was introduced in many countries it did not be­ accidently introduced and established in Europe come established. Permanent mass rearing and without its natural enemies. In addition, resis­ annual releases are necessary ifthe predator is to tance of the Colorado potato beetle to insecticides be used in the program. is more pronounced in Europe than in the United In this study, biological and ecological studies States. For instance, in the United States, Cut­ were conducted to evaluate the impact of a natu­ komp et al. (2) reported a sevenfold to ninefold ral control against P. bioculatus on the pest or increase of DDT3 in LDso for resistant population prey population, L. decemlineata. However, more compared with a susceptible population, whereas importantly, we emphasized the total approach in in Poland, Lakocy (15) reported up to 123-fold in­ evaluating the impact of the natural enemies not crease in LDso's for resistant pests compared with only against the pest but to predict their impact susceptible populations. in preventing plant damage and as a deterrent to Knight (13) reported on the life history and loss in yield. PREDATOR-PERILLUS BIOCULATUS Materials and Methods 237-ml waxed ice-cream cartons with clear plastic lids. Water was provided in a l-dr vial with a cot­ In biology and life-table studies, adults and ton plug slanted downward so gravity flow would nymp~s of P. bioculatus were held individually in keep the plug wet. A 3-cm2 piece ofStyrofoam was· used to prevent the vial from rolling. The photo­ lScience and Education Administration, Yakima Ag­ period (light:dark = L:D) was 16:8 hours per day. ricultural Research Laboratory, Yakima, Wash. 98902. Two temperature ranges were used, 22° ± 1.5° C 2Italic numbers in parentheses refer to Literature for biological and life-table studies and 24° ± 7° Cited, P.l1. for biological studies. 31 j 1,1-trichloro-2 ,2-bis(p-chloropheny i)ethane. In most cases, the immature stages of P. 1 2 bioculatus were either fed larvae or eggs ofL. de­ females laid 127 egg clusters with an average of cemlineata throughout their nymphal stages. In a 17.B ± .6 S.E. eggs per cluster. few experimer.ts, the first- and second-stage nymphs were fed eggs and then switched to lar­ IMMATURE STAGE vae. Nymphs were never given eggs and larvae at the same time. The number ofeggs or larvae con­ The developmental time and the rates of con­ sumed was determined daily. The amount of food sumption of the pr,edator were emphasized based provided always exceeded the amount consumed on diets of either eggs or larvae of L. decem­ by the predator. lineata. In comparing the developmental and con­ The incubation period for eggs ofP. bioculatus sumption rate of P. bioculatus fed on eggs at the was studied in tests conducted in 1975 and 1976. mean temperatures of 22° and 24° C-except for The eggs were held at 22° ± 1.5° C and at 23° the first and second stages, which had almost (range, IBo to 30°) with a 16:B-hour photoperiod. equal developmental time-those reared at the Eggs laid on the same day by one female were lower temperature had a longer developmental placed into a 29 cm3 jelly cup and checked daily period for each nymphal stage. Each additional for mortality and hatching. stage had increased its developmental time by l.0, an~ 1.9 days for the fourth and fifth stages, respectIvely, when reared at the higher tempera­ ture of 24°. The nymphs took IB.2 days to com­ Results and Discussion plete their development at 24° compared with 20.7 days when reared at 22° (table 2). Franz (4), Knight (13), and Landis (14) have EGGS observed that the nymphs ofthe first-instar stage The eggs of P. bioculatus reared at a constant of P. bioculatus do not feed. In the course of our temperature of 22° C had an incubation period of study, ~t was apparent that the first nymphal 7.76 ± .02 standard error (S.E.) days. Eggs incu­ stage dJd not need food to complete its stadium, bated at a temperature of23° hatched in 7.51 days and mortality can be kept at a minimum with an ± .03 S.E. (table 1). From a total of 1,926 eggs, the available moisture source such as a potato leaf. average hatching time was 7.64 days ± .02 S.E.; therefore, for most calculations, egg hatch was rounded to B days. The eggs are barrel shaped and laid in batches. TABLE 2.-Developmental and consumption rates In the field, the eggs are laid on potato leaflets ofnymphal stages ofPerillus bioculatuson eggs and, at times, on the petioles of the leaves.