____ ___________________________ _____________________ Hawaii Island Rat Lungworm Working Group Rat Lungworm IPM Daniel K. Inouye College of Pharmacy RLWL-2 University of Hawaii, Hilo

Integrated Pest Management for Slug and Snail Control in School Gardens

Standards addressed: Standard 5: Political Science/Civics Topic: Citizen Participation

• Demonstrate the role of a citizen in civic action by selecting a problem, gathering information, proposing a solution, creating an action plan, and showing evidence of implementation.

Next Generation Science Standards Engineering Design 3-5-ETS-1 Engineering Design

• 3-5-ETS1-1: Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.

• 3-5-ETS1-2: Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

• 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

MS-ETS1 Engineering Design • MS-ETS1-1: Define the criteria and constraints of a design problem with sufficient

precision to ensure successful solutions, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

• MS-ETS1-2: Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

• MS-ETS1-3: Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.

Common Core Writing Standards K-5: Research to Build and Present Knowledge

• Conduct short research projects that use several sources to build knowledge through investigation of different aspects of a topic.

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• Recall relevant information from experiences or gather relevant information from print and digital sources: summarize or paraphrase information in notes and finished work, and provide a list of sources.

K-8: Research to Build and Present Knowledge • Conduct short research projects to answer a question (including a self-generated

question) drawing on several sources and generating additional related, focused questions that allow for multiple avenues of exploration.

• Gather relevant information from multiple print and digital sources, using search terms effectively: assess the credibility and accuracy of each source; and quote or paraphrase the data and conclusions of others while avoiding plagiarism and following a standard format for citation.

5-ESS3 Earth and Human Activity • 5-ESS3-1. Obtain and combine information about ways individual communities use

science ideas to protect the Earth’s resources and environment.

Math • 5-Measurment and Data. Convert like measurement units within a given measurement

system. • 7-Ratios and proportional relationships • 7-Geometry. Draw, construct, and describe geometrical figures and describe the

relationship between them (mapping). • 7-Statistics and probability. Use random sampling to draw inferences about a population.

Learning Objectives: Students will be able to:

• Describe integrated pest management (IPM) and what defines it as a strategy for managing pests.

• Identify conditions and materials conducive for sheltering slugs, snails and flatworms. • Design, construct, identify, position shelters in the school garden. • Demonstrate safe practices when removing slugs and snails from shelters or garden area. • Demonstrate how to make and safely use a slug jug. • Understand proper disposal of slug jug contents. • Describe how data collection helps in IPM.

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Reading for Understanding:

WHAT IS IPM? Integrated pest management (IPM) practices received wide support when the ecology movement of the 1970’s pressed for the integration of methods for pest control that lessened the negative effect of pesticide, herbicides, and fungicides on ecosystems. Integrated pest management incorporates the least toxic methods for control of pests and includes the careful consideration of available pest control methods including biological, chemical, and cultural practices. These management practices are dynamic and involve monitoring systems to continuously evaluate population levels for decision making and adaptive management. The IPM plan used here is based on the University of California Statewide Integrated Pest Management Program guidelines for snails and slugs, which recommends removing materials where slugs and snails can hide and providing appointed shelters for refuge from the sun and predators. Other cultural practices employed include hand picking, barriers (copper, Bordeaux mixture, ashes or other abrasives), natural enemies (domesticated fowl such as ducks, chickens), and baits.

Introducing IPM in the School Garden for control of slug and snails. Intermediate hosts of Angiostrongylus

cantonensis, the rat lungworm, which can be found in the garden, include slugs, snails, and some species of flatworms that prey on slugs and snails. Flatworms are in a group of organisms called paratenic hosts, which also include prawns, shrimp, crabs, frogs, and water monitor lizards. Rats are called the definitive host of the rat lungworm

parasite, as the lifecycle of the rat lungworm begins in the rat. It is important to control rats to reduce the risk of infection, and rat control should be a part of the school’s maintenance plan. The stages of the rat lungworm parasite that can be found in the rat are not infective to humans or other mammals. The infective stage is only found in slugs, snails, and paratenic hosts, which is why we need to control those organisms in the school garden.

Shelters The best methods of slug/snail/flatworm control for school gardens includes the use of shelters

and handpicking. In cases of heavy infections, a slug/snail bait that is safe for use in school gardens can be used. Baits are considered pesticides, so check the product label, as some may be registered for use in organic gardens but not at schools. Check with the Department of Education’s Integrated Pest Management Division for recommendations. Their staff can assist if you have questions regarding specific products at (808) 586-3452. If a bait is to be used it is important to apply during optimal conditions for maximum effectiveness. We encourage schools

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to include rat control as a part of their maintenance programs but we do not include rat control as part of the school garden responsibility, and so rat control methods are not discussed. It would be advisable to discuss departmental responsibility for rat control with your school principal. You can find more information on slug and snail control and baits at: http://ipm.ucanr.edu/QT/snailsslugscard.html, https://www.pesticideresearch.com/site/?page_id=7404 http://npic.orst.edu/factsheets/ironphosphategen.html.

The use of shelters (traps) are a very useful and important control measure. Shelters allow you to identify your population composition, who do you have in your garden, monitor the numbers of each of the species found, and control populations through removal of individuals found. Slugs and snails will follow slime trails and, over time, attraction to the shelters by these pests will increase. Do a slug hunt to see where slugs and snails may be hiding in the

garden. If you have plastic, tarps, shade cloth etc. in the garden you may find they are already using these sheltering materials and you may just want to leave them, but only if you use them as shelters and check and remove those found on a regular basis. If you are making shelters, the best materials we have found and have shown the greatest capture rates, have been cardboard, which works well for many slug species, raised wooden boards for snails, and folded plastic or tarp material for semi-slugs and other species. You may find there are other materials that are effective in your garden. If using plastic, use a heavy mil plastic, such as a heavy-duty yard trash bag. Cut the bag on the sides to fully open it. When checking this shelter, you will want to be able to open it all of the way up and check both sides. Fold the bag, sprinkling with water with a little water as you go if conditions are dry, until the folded bag is about 0.61m2 (2ft2). Place a rock on the bag or pin it to keep it from blowing away. You can attach a piece of duct tape and put a label on the shelter so it is not mistaken for trash. Semi-slugs in particular like cat and dog food, and a one-time application of a few kernels of dry food under a shelter works well as an attractant, but do not overdo it so you are not attracting rats.

The shelters do not have to be large, a 0.61m2 shelter is a good size that does not take up much room in the garden and will often harbor large numbers of slugs, snails, flatworms, and other interesting species such as spiders and lizard eggs. Shelters can provide a dual purpose as they will also help keep weeds down. Many gardens use weed cloth for weed suppression and slugs

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like to hide under this material. If you use weed cloth in the garden it is important to regularly pull it back and check for and remove any slugs, snails, or flatworms. Through adaptations of the shelter environment, we can learn what different species of slugs, snails, and flatworms prefer, and devise the perfect shelter for your most abundant visitors.

Ground preparation, shelter checking, innovation It often helps to clear of vegetation below the shelter and moisten the soil under the shelter to

provide favorable conditions attractive to slugs and snails for a shelter place to hide out the daylight hours. A layer of wood chips under the shelter can help retain moisture and provides a good habitat for many species, such as the Cuban slug. Shelter checking and recording should be the responsibility of the school garden teacher and the students, and should be done on a regular basis. Weekly collection is advised. In addition to trapping slugs and snails with the shelters, searching for the pests and manual collection is an important and effective method of control. Garden searches can be done regularly by students and they can learn where in the garden slugs and snails are hiding and what they might be attracted to. From our experience, students enjoy the slug/snail hunt and it’s a great way to get them to sharpen their observation skills. A fermented beverage trap, that mimics a beer trap but is not alcoholic, may be a good method for trapping slugs. Students at one school cut the top 1/3 off of a plastic water bottle, inverted the top into the bottom section and taped it shut. They then added different solutions they thought might attract slugs. As students begin to identify the conditions that these garden pests like they can use critical thinking skills to devise shelters and use the scientific methods to determine what works best for your school garden.

Data Collection Data collection is integral to the scientific

method and is a crucial part of IPM as it gives factual evidence as to the effectiveness of your management plan. The regular collection of data can alert us of the arrival of a new species, especially those that are important carriers of the rat lungworm parasite such as the semi-slug Parmarion martensi. This species is currently only thought to be established on

Oahu and Hawaii Island, but was recently discovered on Maui. Early detection of this species is important in areas where it has not been recorded as it can then be targeted for control. Data collected should include the date, weather conditions, rainfall (weekly), the species found, how many of each species found, and under what shelter type or on what material they were they found. The data collected can be analyzed in math classes using pie charts, bar graphs, scatter plots, and trend lines, and help you understand population fluctuations as they relate to weather and time. Additionally, data collection by Hawaii school garden projects can provide critical information that can be used by the Hawaii Dept. of Agriculture and the Hawaii Dept. of Health. As citizen scientists, student data can help these departments target important carriers of the rat lungworm parasite and predict disease outbreaks.

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A sample data sheet is shown below. The species type is labeled in the “species” column, and tick marks are used to show how many of each species are found in each shelter type (cardboard, plastic, etc.) column. Data should include the student’s name, date, weather conditions, weekly rainfall amounts, species, quantity of species, and shelter type where found. A category “other” includes all non-shelter locations where

slugs, snails, or flatworms are found.

School _______________________________________________ Island ________________ GPS coordinates___________________ Elevation___________________ Date________________ Weather______________________________ Rainfall amt.__________________ Moon phase (optional)________________________________________ Data collected by__________________________________________________________

Species Cardboard Plastic Wood Other

Comments:

Safety Precautions All slugs and snails can potentially be carriers of the rat lungworm parasite and so care should be taken when collecting them. It is important to never touch slugs, snails, or flatworms with your bare hands. Always pick up these garden pests by using tongs, chopsticks, or even a plastic bag. We encourage students to wear gloves in the garden, and especially when collecting slugs.

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Disposal of Slugs and Snails: The Slug Jug The Slug Jug is a homemade container filled with a solution of 7 parts water to 1 part salt, in which you can safely dispose of slugs, snails, and flatworms you find in the garden and under your shelters. The high salt content in the jug will kill the slug, snail, or flatworm, as well as any rat lungworm parasites it might be harboring. We recommend using a one-gallon, wide-mouth plastic jar. You can usually get these by asking a restaurant or fast food establishment for their empty

jars. If you have many large snails, such as the giant African snail, you can use a 5-gallon bucket with a lid. Write “Slug Jug,” on the outside with a waterproof marker along with an appropriate warning to prevent anyone from handling or drinking the contents. Add seven parts (cups, liters, etc.) water, and one part salt (7:1 ration) to the jar and stir until the salt dissolves. It’s a good idea to keep the tongs or chopsticks used to pick up the pests with the jug. To create a tongs holder, tape a container (e.g., plastic bottle with top cut off, recycled can, etc.) to the side of the jug using duct tape. When adding a pest to the jug avoid splashing and do not look directly into the jug. The slug jug will get smelly from the decomposing contents but this is the price we pay for resisting the use of pesticides and opting for the least-toxic methods. You can continue to add these slimy pests to the jug until you think it is full enough or smelly enough and needs emptying. It’s best to wait a week from when the last slug or snail is added to when the jug is emptied in order to make sure any parasites that might be in an intermediate host are dead. As the salt water will kill plants it is best to empty the contents on a gravel area or in an area where you do not want weeds or any plants to grow. You can also dig a hole in an area where you don’t want plants to grow and bury the contents. Clean the jug with water and then refill with water and salt. It may be beneficial to have several of these slug jugs available for easy access in the garden.

Activity: Design and implementation of IPM in the school garden or school grounds. Team activity: 3-5 students per team is ideal.

• Population analysis: Students, under the direction of the teacher and using safety precautions, will work in teams of 2-4 students and conduct a search, or hunt, to determine presence of slugs and snails in the school/school garden area.

• Preliminary identification: Students will draw and write descriptions of organisms found.

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• Mapping: Students will map the school garden (or school grounds) with the school garden teacher. Through discussions, sites will be identified in which to locate shelters for slug and snail management.

• Slug Jug station design: Having a known location where the slug jug handy with the proper safety implements, and the data collection sheet is kept is important for ease and success of disposing of slugs, snails, and flatworms, and for consistent data collection. Students will design on paper a prototype station(s) where the slug jug can be safely stored along with tongs, gloves, and laminated data collection sheet with a marker pen. Acceptable designs will be constructed, possibly with support from a technology class or with parental or a volunteer work party. Students will make a slug jug that is properly labeled and filled with a 7:1 saltwater solution that will be easily available for use in the garden.

• Shelter design: Student teams will identify the type of material(s) to be used for shelters and provide written evidence for their decisions.

• Site preparation: Students will prepare shelter site, which may involve clearing of vegetation and providing a moist substrate (soil, wood chips, compost).

• Site checks and data collection: With teacher approval, student teams will check shelters and record data.

• Pest removal: Students will safely remove any slugs, snails, or flatworms found using the slug jug.

• Data transfer: Students will be responsible for correctly transferring the data collected in the garden onto a Google Sheet in the classroom.

• Take the information home: A goal is for students to encourage their families to control slugs and snails at home. If we are to reduce the rates of host infection it is important for a wide-scale, control efforts to be made.

Further studies to learn more about invasive snails in the U.S., and why IPM

• The official USDA response to invasive pest snails. https://www.npdn.org/system/files/WPDN%20Robinson%20two%20cases%202015.pdf

• Read Rachel Carson’s “Silent Spring” (1962). A lesson-plan on this important literary work titled “Rachel Carson: Sounding an Environmental Alarm” by Earth Day Network for grades 5-8 can be found at: http://wwwtc.pbs.org/wgbh/americanexperience/media/uploads/earthdays_tg_rcarson.pdf

• Students can learn about Cesar Chavez, a champion for farm workers in California in the 1970’s who started a nation-wide boycott of California grapes to highlight the dangers of farm worker exposure to pesticides.

Things to think about: What other invasive species can you identify that present problems for Hawaii’s ecosystems and residents? What management practices are used to control them?

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This material is written by Kathleen Howe and produced by the Hawaii Island Rat Lungworm Working Group with funding from the Hawaii Invasive Species Council and support from the Daniel K. Inouye College of Pharmacy. Photo credit: Jarvi lab.

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