Biocontrol Photo © by Vivian Kimball by Annie Reid Has biocontrol come of age? To see a Environmental science students from class of high school students wading in Westborough High School dig Purple a marsh of cattail and purple loosestrife, Loosestrife root balls in a flooded digging root balls in April or counting cattail marsh in April. and measuring stems in September, you might begin to think so. the quality of the natural environment in Biocontrol is the use of one organism Westborough, a town blessed with sev- – the biocontrol agent – to control another eral ponds, five major swamps, and the organism that is a pest to humans. In headwaters of the Assabet and Sudbury this case, the pest is the invasive wet- Rivers. Purple loosestrife had invaded land plant, purple loosestrife (Lythrum our wetlands over the past 20 years. With salicaria), and the biocontrol agent is a biocontrol project like the one we had loosestrife-leaf-eating bee- read about, we could also bring a real, tles. Both purple loosestrife and these hands-on environmental project to the are originally from Europe. next generation of environmentalists, The Westborough Purple Loosestrife the town’s young people. Biocontrol Project began when a few We instantly had second thoughts. A members of the Westborough Commu- biocontrol project using a non-native nity Land Trust (WCLT) read a newspaper organism is fraught with perils. The past article in 2008 about a high school teacher provides scary examples of non-native and class in Uxbridge who were raising plants or being introduced inad- and releasing beetles to control purple vertently or deliberately (for biocontrol loosestrife. It inspired us. or other purposes) and going on to cause Our first thought was that a similar major environmental harm. project would fit the land trust’s environ- An infamous case is the Indian mon- mental and educational aims. By control- goose (Herpestes javanicus), introduced ling purple loosestrife, we could improve from Asia to the Hawaiian Islands in  the 1880s to control rats on sugar cane defoliate trees in the northeastern U.S. plantations. Things did not go as planned on a large scale during outbreaks. In because the mongoose hunts during the 1869 E. Leopold Trouvelot, then an art- day while the rats come out primarily at ist and amateur entomologist (and later night. It turned out that the mongoose an astronomer and faculty member at Biocontrol hunted many native Hawaiian ground- Harvard), first brought gypsy moth cat- nesting birds and their eggs. These birds erpillars from Europe to Medford, MA. include Hawaii’s state bird, the Hawaiian There he tried to breed them to produce Goose or Nene (Branta sandvicensis), silk, but some escaped into his neighbor- which is today a state and federal endan- hood and spread from there. By 1889 gered species. the Massachusetts State Board of Agri- Even purple loosestrife could be con- culture was already trying to eradicate sidered an example of an introduced the gypsy moth, but its efforts proved species gone wrong. The plant arrived futile. Today, invasive gypsy moths have on North American shores in the early spread throughout the northeastern U.S. 1800s, probably as seeds in the ballast and parts of the midwest, southeast, and of ships and as an import for people who eastern Canada. wanted it in their gardens for medicinal or A less well-known part of the gypsy ornamental uses. It outcompetes native moth story involves a non-native tachinid wetland plants here and has become a fly, Compsilura concinnata, which was major invasive species. introduced as early as 1906 to control A dramatic example that New England- the gypsy moth. This fly is a parasitoid ers are quick to bring up is the gypsy that injects its larvae into caterpillars moth (Lymantria dispar). Its caterpillars of the gypsy moth (and many other Photos © by Bill Byrne Purple Loosestrife typically dominates wetlands, forming dense monocultures. Bees love it (inset), but it suppresses many native plants and animals. Scenes similar to this one are common in many areas of Massachusetts. People brought this invasive plant from Europe in the early 1800s for ornamental and medicinal uses, and seeds are also likely to have arrived in ships’ ballast.  ), where the larvae feed and de- Why not use conventional weed control velop, eventually killing the caterpillars. methods against purple loosestrife, such Unfortunately, this Compsilura fly has as pulling it up, mowing or chopping recently been implicated in the decline in it down, or burning it? Or why not use the northeastern U.S. of our showy native herbicides? giant silk moths, such as the cecropia To address these three concerns, we moth (Hyalophora cecropia), promethea checked into the research that had been moth (Callosamia promethea), and buck done. We learned quite a bit about what moth (Hemileuca maia maia). (These makes purple loosestrife so invasive moths are not closely related to the do- and so hard to control, and about what mesticated Asian silkmoth, Bombyx mori, makes the Galerucella beetles suitable which humans have bred to produce silk as a biocontrol agent for it. for 4,000 years.) Starting with the third concern, we found out that conventional weed control Overcoming Reservations methods such as pulling, mowing, chop- The basic concerns about biocontrol ping, and burning are not only expensive are three. Two of them focus on the risks and labor intensive, but also don’t work. associated with introducing a non-native Or rather, they might work only for small, organism. The problem is often that a isolated infestations in well-defined non-native organism is, or proves to be, areas. Purple loosestrife is a perennial a generalist where food is concerned. In wetland plant that can sprout from pieces other words, plants other than purple of roots or stems. Unless control efforts loosestrife might be at risk from a non- remove all parts of the plant from the native biocontrol agent. ground, it just comes up again. And of A generalist diet is much of the problem course it also grows from seeds, which both with the inadvertently introduced it produces in mind-boggling numbers gypsy moth caterpillars and the Compsi- – up to 2-1/2 million seeds per year for lura fly that was intended to control them. a bushy, multi-stemmed plant. Its seeds Gypsy moth caterpillars prefer to feed on also last several years in the soil’s seed oaks (Quercus species) but also eat many bank. other species, even conifers. The Comp- Because purple loosestrife is a wetland silura fly uses gypsy moth caterpillars as plant, chemical control is also out. Herbi- hosts for its larvae, but also attacks 200 cides aren’t suitable for use in wetlands other North American insects in this way, or near our water supplies. including the lovely giant silk moths. The Regarding the first and second con- danger is that a non-native biocontrol cerns, we learned that researchers had agent for purple loosestrife might feed started screening European insects as on more than one species of plant in its possible biocontrols for purple loose- new environment. That is, it might not be strife in the 1980s. Investigators eventu- adequately host-specific. ally focused on six insects: two leaf-eating One precaution would be to use a bio- Galerucella beetles, a root-mining weevil, control agent that is host-specific. We a flower-feeding weevil, a seed-feeding would need one that has been proven weevil, and a gall midge. Finally, after to specialize in eating only the purple six years of research in the U.S. on the loosestrife. safety and efficacy of the twoGalerucella The second concern is long-term. Even beetles, in 1992 the U.S. Department of biocontrol agents that are host-specific Agriculture approved their use as a bio- might eventually adapt and evolve to at- control for purple loosestrife. The two tack a broader group of organisms. We species, Galerucella calmariensis and would want to know that a host-specific Galerucella pusilla, are closely related biocontrol agent had been tested with oth- and similar-looking. They are typically er plants, including those closely related used together. to purple loosestrife, and found safe. These Galerucella beetles are tiny, Finally, a third concern that we had to delicate-looking, tan beetles measur- answer, both for ourselves and for oth- ing only 3/16 of an inch long. There’s ers, was: Why resort to biocontrol at all? no confusing them with the big inch-  Photos © by Garry Kessler Galerucella beetles are tiny, delicate-looking, tan beetles measuring only 3/16 of an inch long. They mate and lay eggs on purple loosestrife in the spring after overwintering in the nearby soil. long invasive Asian long-horned adult beetles lay their eggs on the stems (Anoplophora glabripennis), a generalist of purple loosestrife in May-June. When that threatens maple, elm, willow, birch, the larvae hatch a few weeks later, their horse chestnut, poplar, ash, and other food supply is right there, and they eat trees in the Worcester area and in the the leaves and especially the new growth forests beyond. of purple loosestrife – the meristematic The Galerucella live about a year and tissue. are active in spring and summer when When the larvae are ready to pupate, purple loosestrife plants come up and they go into the soil near their host plant. bloom. The beetles overwinter in the After a metamorphosis that’s similar to soil in fall and winter when the purple the process of caterpillars becoming loosestrife plants go dormant. butterflies, new adult beetles emerge These beetles are very host- specific. from the soil in July-August, when purple They specialize in eating purple loose- loosestrife is blooming. At this point, they strife in more than one life stage. The may fly up to two-thirds of a mile to find adult beetles eat purple loosestrife purple loosestrife leaves to eat. Then at leaves, but it’s their immature eating-and- summer’s end, as the purple loosestrife growing stage – the caterpillar-like larvae plants die back, the beetles go back into – that does the major damage to purple nearby soil to overwinter. Finally, when loosestrife while feeding voraciously on the beetles emerge again the next spring, new growth in the spring. they may disperse up to 10 miles to find purple loosestrife. They again eat purple Not only do these Galerucella eat purple loosestrife leaves and then get on with loosestrife, but their whole life cycle the business of mating and laying eggs also revolves around the plant. Like 85 before they die. percent of insects, Galerucella beetles go through four life stages: egg, How readily might these Galerucella or caterpillar, pupa, and adult. First, the switch to new host plants? We learned  Photos © by Garry Kessler Purple Loosestrife flowers produce abundant nectar that attracts bees and wildlife such as this Hummingbird Clearwing Moth, as well as Monarch and Black Swallowtail butterflies. Charles Darwin studied pollination in Purple Loosestrife in England in the mid-1800s. that researchers tried raising Galerucella On the other hand, we also found that on closely related native plants, including we could expect the beetle population Decodon verticillatus, often called swamp to be regulated in a density-dependent loosestrife or water-willow, and Lythrum manner, varying with the size of its alatum, known as winged loosestrife. food supply. If the beetles ate most of They found that the Galerucella might the purple loosestrife, there would be sometimes nibble other plants, but the less food available and the size of future larvae do not grow to maturity or com- beetle populations would diminish. If the plete their life cycle on them. Basically, purple loosestrife population started to the larvae don’t survive unless they have recover when there were fewer beetles, a diet of purple loosestrife. there would be more food and the beetle Like many of our friends and fellow population would consume the bounty townspeople, we wondered what would and increase rapidly. happen if Galerucella beetles worked so We realized that Galerucella beetles well as biocontrol agents that they ate would not eradicate purple loosestrife. all the purple loosestrife in the local The plant is probably here to stay. But area. On one hand, we learned that the we figured we might reasonably expect beetles disperse considerable distances the Galerucella beetles to reduce the to find their specific host plant – up to size and dominance of purple loosestrife two-thirds of a mile when the new adults populations. In our minds, this outcome first emerge and up to 10 miles when the would be satisfactory. In spite of its overwintering adults re-emerge – so they status as an invasive, purple loosestrife would likely fly off to new locations. has its fans. For example, in addition  to its beauty and traditional medicinal decide to hurry the process along by uses, it produces abundant nectar and undertaking our own purple loosestrife is valued by beekeepers and farmers biocontrol project. who keep bees. It would be fine with us if purple loosestrife were to become one Starting the Project wildflower among many, as it is in its na- tive Europe. We would be glad if it were Our first step was to get various approv- no longer the “pretty purple plague,” as als and permissions. We discussed plans one newspaper article dubbed it. for the project with the Westborough Conservation Commission and sought We were surprised to discover that the permission from the landowners of the Galerucella beetles had already been in properties where we wanted to release use in Massachusetts for at least a dozen the beetles. We obtained permission from years. In the mid-1990s the U.S. Fish Mass DCR, which controls the shoreline and Wildlife Service started releasing of Mill Pond, a SUASCO flood control them in two national wildlife refuges in reservoir built in 1968-70 at the south eastern Massachusetts, Great Meadows end of town and now lined with purple and Parker River. Starting in 2000, the loosestrife. The Mass Division of Fish Massachusetts Wetland Restoration and Wildlife (DFW) gave us permission Program (WRP) began using them, and to release beetles at its Westboro Man- Mass Audubon and the Mass Department agement Area in the north end of town. of Conservation and Recreation (DCR) This area included a cattail marsh that started doing so in 2006. By 2008, the purple loosestrife was taking over – a beetles had already been released in at classic example of the struggle between a least 43 sites in eastern Massachusetts. native wetland plant and invasive purple In our area of central Massachusetts, loosestrife. One of the town’s conserva- not only had the high school class in tion commissioners also offered the farm Uxbridge released Galerucella, but the pond on his property as a release site. conservation commission in neighboring Grafton had also done so. These approvals and permissions en- tailed getting others. We needed approval We knew that the beetles were already from the Mass Historical Commission out of the bottle, so to speak. It was clear to make sure we would not be digging that they would follow the loosestrife root balls at any historically important and eventually spread to Westborough. locations. Just to be on the safe side, This knowledge made it easier for us to we checked with the Mass Natural Heri- tage and Endangered Species Program (NHESP) and found them to be very encouraging. They had already used Galerucella beetles in various locations to prevent purple loosestrife from over- whelming endangered wetland species. We sorely needed practical advice and guidance regarding the “how to” aspects of the project. The Mass Wetlands Resto- ration Project was already winding down in 2009, but pointed us to their guidelines and protocols for purple loosestrife

Five years before this photo was taken, this marsh in the DFW Westboro Management Area was dominated by native cattails. Now it is mostly purple loosestrife. Initial monitoring data collected by Westborough High School students showed that purple loosestrife stems outnumbered cattail stems by 5 to 1.  Photo © by Garry Kessler The Purple Loosestrife biocontrol project is low tech and inexpensive. Each spring, Westborough High School students raise a new generation of Galerucella beetles in simulated wetlands created by placing potted Purple Loosestrife plants in plastic wading pools half-filled with water. Net prevents the beetles from escaping. 10 biocontrol. They recommended that we do other purple loosestrife biocontrol contact the regional watershed organiza- projects throughout the state. tions with whom they had worked. They The project is low-tech and inexpen- also assured us that we would be able to sive. So far it has cost us less than $500 order “starter beetles” under their Mas- a year. The closely entwined life cycles sachusetts license. of purple loosestrife and the Galerucella We ended up working with the Neponset beetles determine the timing of various River Watershed Association (NepRWA), activities. based in Canton, which was running its Every April, the students create a own large-scale biocontrol project with simulated wetland in the greenhouse by 50 volunteer “beetle ranchers” from the digging up purple loosestrife root balls, community. NepRWA kindly invited us planting them in pots, and then setting to their training sessions and included the pots in plastic wading pools half-filled our small order for starter beetles with with water. After the plants have grown their own much larger one (from the for about a month, students introduce New Jersey Department of Agriculture). starter beetles onto each plant and cover In return, we helped with some related the plants with sleeve cages of netting tasks, such as dividing up shipments of to keep the beetles from escaping. These thousands of chilled Galerucella beetles beetles eat some loosestrife, mate, lay and placing them into hundreds of plas- eggs, and die. Larvae hatch, eat, grow, tic cups containing 15-20 each. We also and pupate to yield a new, much larger got good practical advice from a middle generation of beetles. The new beetles school teacher in Sudbury who had been begin to come out of the soil in midsum- raising and releasing Galerucella beetles mer, when purple loosestrife is typically with seventh-graders. in bloom. Land trust volunteers transport Back in Westborough, we were excited the potted plants to our release sites, to find enthusiastic partners at Westbor- remove the netting, and leave the pots ough High School (WHS). Ms. Anita Lotti, in place for several weeks as beetles a chemistry teacher who also taught continue to emerge. environmental science and advised the As expected, the greatest damage environmental club, was interested. The to purple loosestrife takes place each chairman of the science department was spring. In the wild, the new beetles over- very supportive. As luck would have it, winter in the soil and crawl back out in the high school had a small greenhouse May to eat, reproduce, and die. Their on the third floor that was not in use. larval offspring – yet another, even larger Eventually, in the second year of the generation – destroy growing plant tissue project, we also welcomed participa- as they eat their way to maturity. tion by a Girl Scout who raised beetles Every spring and fall, WHS students out-of-doors and supplied 30 percent of and WCLT volunteers collect monitor- the beetles released that year as part of ing data for the project. We have set her Gold project (the equivalent of a Boy up square-meter quadrat frames at our Scout Eagle project). release sites and use protocols and reporting forms (originally designed at Combatting Cornell University) from the Wetlands Restoration Project. Spring monitoring Purple Loosestrife involves looking for Galerucella beetles, In 2011 we are in the third year of eggs, and larvae within the quadrats. a planned 5-year biocontrol project. Fall monitoring focuses on counting and Each spring, Westborough High School measuring stems and inflorescences of students raise a new generation of Gale- purple loosestrife, cattail, and other rucella beetles. Westborough Community plant species. Comparisons over five Land Trust volunteers release these years should give us a formal view of the beetles in wetlands during the summer effects of the project. when school is out. To monitor progress, Informally, we’ve seen some interesting students and land trust volunteers collect progress so far. In spring 2010, the year field data each spring and fall, using the following our first release, we noticed same standard forms and protocols as 11 Galerucella beetles eating and mating outfit the students with hip waders and on purple loosestrife at many locations purchase other supplies for her class. We around town. We were excited to see that are grateful for donations of gently used beetles had indeed overwintered and wading pools and 3-gallon plant pots from were busy reproducing in the wild. By families, individuals, Bigelow Nurseries late summer, the purple loosestrife on of Northborough, and members of the part of the Mill Pond shoreline, down- Westborough Garden Club. wind from our release site, was visibly What do our student partners at WHS damaged. The plants were brown and get out of the project, besides muddy stunted. We’ve noted the same effects in feet? Their teacher, Ms. Lotti, sums it spring 2011. It’s possible that the beetles up best: we saw came from out of town as well as from our releases. But one way or “The project gives students a unique another, biocontrol of purple loosestrife hands-on way to apply concepts they is underway in Westborough. have learned in class – , ecol- ogy, and invasive species – to real life. We are pleased to have received local They also gain real experience in collect- funding for our biocontrol project, includ- ing and analyzing field study data. And ing a Staples Education Grant and a West- they develop a sense of what it might be borough Civic Club grant. Ms. Lotti also like to work as an environmental scientist. obtained a grant from the Westborough The project is also part of their service Education Fund, which enabled her to learning – they’re learning to take care Photo © by Vivian Kimball The greatest damage to Purple Loosestrife plants comes when the caterpillar- like Galerucella larvae feed voraciously on growing plant tissue in the spring. The larvae are gold-colored and about ¼ inch long by the time they are ready to pupate in the soil and transform into adult beetles. 12 Photo © by Anita Lotti The Westborough High School environmental science class of spring 2011 was the third group of “beetle ranchers” in the Purple Loosestrife biocontrol project undertaken by the Westborough Community Land Trust and Westborough High School. of their own community, to give back to way to find and test biocontrol agents for their community.” the woolly adelgid that is destroying our We are taking local action to combat hemlocks and for the non-native phrag- purple loosestrife, but a walk past just mites that continues to spread through about any wetland in nearby towns our wetlands. reminds us that purple loosestrife is a Has biocontrol come of age? If high regional problem. For this reason, the school students can do it, and if research- Westborough Community Land Trust ers can provide tested, host specific recently joined the SuAsCo Coopera- biocontrol agents for other high-profile tive Invasive Species Management Area invasive species, perhaps so. (SuAsCo CISMA). This new organization brings together conservation colleagues The Westborough Community Land from a variety of non-profit, municipal, Trust (WCLT) is a member-supported, all- state, and federal organizations and volunteer nonprofit organization dedicated agencies to form new collaborations to preserving open space and furthering and exchange information for more ef- environmental education in Westborough, fective invasive species control. Several MA. Annie Reid is an active member who members of this group have engaged in writes a Nature Notes column for WCLT their own beetle ranching and purple in the Westborough News and works as loosestrife biocontrol projects, as well as a freelance college textbook editor. Garry control efforts targeting other invasive Kessler is an amateur nature photographer, species. past president of WCLT, and software engi- We are hopeful that collective efforts neer. The couple has lived in Westborough at controlling invasive species will help for more than 30 years. Vivian Kimball is a to preserve the wonderful natural en- director of WCLT and graduate student in vironments of New England for future conservation biology. Anita Lotti has taught generations. We’ve been interested to chemistry and environmental science at learn that research efforts are under Westborough High School for 7 years. 13