• Foreword
• Introduction
• Characteristics of adult golden apple snails
• Mode and signs of damage
  
• Life cycle
• Where they live
• Feeding habits and host range
• Naturally occurring biological control agents
• Management options
• Integrated management scheme based on rice growth stages
• New information
• Nutritive value of golden apple snail
• List of Fertilizer and Pesticide Authority-registered molluscicides as of 31 March 2000
• References
• Acknowledgements
• About DA-PhilRice
• Contact / more information
• Related pages on applesnail.net
• Links

Foreword

The golden apple snail, popularly known as "golden kuhol'' [Pomacea canaliculata Lamarck], is one of the major pest problems in rice production. In 1989, the Food and Agriculture Organization of the United Nations estimated that yield tosses owing to this pest ranged from 1% to 40% of the planted area in the Philippines, resulting in huge production loss.

To control this pest, many farmers resort to the massive use of synthetic molluscicides that are expensive and broad spectrum, affecting non-target organisms including human beings.

This primer was prepared to present additional alternatives and information on golden apple snail management. It contains many new information to reduce the misuse of molluscicides. Discussed here are details of the biology of golden apple snail, including several management options that farmers could use to manage this pest in their farms.

A new recipe for golden apple snail is now available. The product is a chicharon (cracker) that is devoid of water, has no offensive odor, with longer shelf-life, and can be readily used as an ingredient in other recipes.

We hope that this primer wilt help our agricultural technicians, extension workers, and farmers better understand the nature, spread, and management options for golden apple snail.

Leocadio S. Sebastian Executive Director

Introduction

The golden apple snail, popularly known as "golden kuhol" [Pomacea canaliculata Lamarck], was introduced into the Philippines between 1982 and 1984. It came from South America (Brazil and Argentina) via Taiwan. Its high nutritive value as food for human beings and farm animals generated interest among both public and private sectors to propagate the production of this organism. However, a few years after its introduction, the golden apple snail became a major pest of rice.

Of the 3 million (M) hectares of rice lands in the Philippines, 1.2-1.6M hectares are infested with golden apple snail. In 1990, P212M was spent to control this pest. The first account that it had become a major pest was recorded in 1986 when about 300 hectares of irrigated rice farms in Region 2 (Cagayan Valley) were heavily damaged. Since then, rice area infested with this pest has been increasing until it became a national menace.

Characteristics of adult golden apple snails

The golden apple snail lives for 2-6 years with high fertility.

Shell is tight brown; flesh is creamy white to golden pinkish or orange.

Size depends on the availability of food.

Most destructive stage is when the length of the shell is from 10 mm (about the size of a corn seed) to 40 mm (about the size of a pingpong ball).*

Female golden apple snail operculum (a1) is concave white it is convex in male (a2).

The shell of the female adult snail (b1) curves inward; the male shell (b2) curves outward.*

Based on the study conducted by MS Dela Cruz, RC Joshi, and AR Martin.

Mode and signs of damage

• Newly-transplanted rice seedlings up to 15 days after transplanting are vulnerable to golden apple snail damage; from 4 days to 30 days after sowing for direct-seeded rice.

• Golden apple snails devour the base of young seedlings. They can even consume the young plants in a whole paddy overnight.

• Missing hills

• Floating cut leaves on the water surface.

Life cycle

• Eggs are [aid at night on any vegetation, levees, and objects (e.g. twigs, stakes, stones, etc.) above the water surface.

• Egg masses are bright pinkish-red and turn light pink when about to hatch.

• Eggs hatch in 7-14 days.

Hatchlings and adults

• Hatchlings grow and mature fast. They are voracious feeders.

• Adults mate for 3-4 hours anytime of the day among crowded plants where there is continuous water supply throughout the year.

• Golden apple snails reproduce rapidly. They can lay 1000-1200 eggs in a month. Thus, egg destruction is a very effective control strategy.

Where they live

• Ponds, swamps, irrigated fields, canals and water-togged areas.

• They bury themselves in moist soil during the dry season. They can aestivate for 6 months, then become active again when the soil is flooded.

• They can survive harsh environmental conditions such as pollutants in the water or low oxygen levels.
  

Feeding habits and host range

• Golden apple snails feed on a wide range of plants such as algae, azolla, duck weed, water hyacinth, rice seedlings, and other succulent leafy plants.

• They prefer young plant parts that are soft because it feeds by scraping plant surface with its rough tongue.

• They also feed on any decomposing organic matter.

Naturally occurring biological control agents

• Red ants feed on the eggs.

• Ducks eat the flesh and young snails.

• Human beings eat the flesh when it is property cooked.

• Field rats bite on the shell and eat the flesh.

Management options

During land preparation

• Before the final harrowing, handpick golden apple snails from rice paddies in the morning and afternoon when they are most active and easy to find.

• Use plants that contain toxic substances against golden apple snails. Examples are gugo (bark) [Entada phaseikaudes K Meer], tubangkamisa (leaves), sambong (leaves) [Blumea balsamifera], tuba-tuba (leaves), gabihan (leaves) [Monochoria vaginalis], tobacco (leaves) [Nicotiana tabacum L], calamansi (leaves) [Citrus microcarpa Bunge], tubli (roots), makabuhay (leaves) [Tinospora rumphii Boerl], and red pepper (fruit).

• Other reported plants include starflower (leaves) [Calatropis giganta], neem tree (leaves) [Azadirachta indica], and asyang [Mikania cordata] contain substances that can kill golden apple snails. These are highly recommended before transplanting rice. Simply construct small canals to confine the golden apple snalts and right there place the leaves of the said plants.

• Use attractants such as leaves of gabi [Colocasia esculenta], banana [Musa paradisiaca L.], papaya [Carica papaya L.], trumpet flower, and old newspapers for easy collection of golden apple snails.

• During the last harrowing, construct deep strips (at Least 25 cm wide and 5 cm deep) in the paddies by pulling a sack containing a heavy object. Provide 10- 15 m distance between strips. Likewise, construct small canals (25 cm wide and 5 cm deep) along the edges of rice paddies.
  

  Small canals, where the golden apple snails will seek refuge if water level is critical, make collection easier.

• Place a wire or woven bamboo screen on the main irrigation water inlet and outlet to prevent the entry of hatchlings and adults. This also facilitates collection of trapped golden apple snails.

Screens on the water inlet reduce entry of golden snails to the paddy.

During transplanting

• Follow the standard seeding rate and distance so that the plants will have sturdy stems.

• If golden apple snail is a big problem, transplant 25-30-day-old seedlings of early-maturing varieties. In the rice areas of the Cordillera highlands, use 30-35-day-old seedlings of late-maturing varieties.

• Put bamboo stakes on water-logged areas in the paddies or near canals to attract adults for egg laying. This makes collection and crushing of the egg masses easy.

• Maintain shatlow paddy water level (2-3 cm shallow) starting 3 days after transplanting.

• Drain the field occasionally to limit snail mobility and feeding activity.

Draining the field occasionally will limit snail mobility and feeding activity.

• Collect, cook, then eat the golden apple snails, or crush and feed them to ducks and pigs. Collection is easier by using attractants such as leaves of gabi, papaya, and trumpet flower.

• Use varieties that are high-tittering and least preferred by the golden apple snails such as PSB Rc36, Rc38, Rc40, and Rc68.

Handpicking is recommended for large adult golden snails as these are not fed upon by ducks.

After harvesting

• Herd ducks in rice paddies immediately after harvest up to the last harrowing for the succeeding crop. Herd them again 30-35 days after transplanting (DAT) early-maturing varieties and 40-45 DAT late-maturing varieties.

Integrated management scheme based on rice growth stages

New information

A study conducted by researchers MS Dela Cruz, RC Joshi, and AR Martin from 1999 to 2000 at PhilRice Maligaya found the following:

• Varieties that are least preferred by the golden apple snails are PSB Rc36, Rc38, Rc40, and Rc68.

• Basal application of complete fertilizer and urea incorporated with the soil at recommended rate during the last harrowing reduced golden apple snail population up to 54%.

• Commercial molluscicides (niclosamide and metaldehyde) were effective against golden apple snails that are directly hit. Their efficacy tasted 2-3 days. Molluscicides may no longer kill golden apple snails that will emerge to the soil surface after aestivating and those that would reenter the treated fields. Niclosamide 250EC at half the label recommendation (0.5 li/ha) killed about 80% of the golden apple snails that were sprayed on. Nictosamide kills more native snails than metaldehyde formulations.

• The Chicharon (cracker) golden apple snail recipe* was improved.
  
  Ingredients
  
  1 kg of golden apple snail flesh
  1 cup vegetable cooking oil
  1/2 cup cornstarch or flour
  1 tsp black pepper
  1/4 cup soy sauce
  3 tbsp vinegar
  3 cloves garlic
  1-2 red chili
  1/2 tsp alum (tawas)
  1 egg
  
  
  Procedure:
  
  1 . Gather 4-6 kg adult golden apple snail, from which some 1 kg flesh wilt be extracted.
  2. Soak the golden apple snail with shell in tap water for 24 hours to remove undigested food. Those that float are dead. Remove them.
  3. Bolt the golden apple snail in a big kettle for 20-30 minutes.
  4. Extract then clean the flesh of golden apple snail. Rinse the flesh with alum (tawas) to remove the unpleasant odor.
  5. Mix all spices with the golden apple snail. Marinate for 24 hours.
  6. Sun-dry the marinated golden apple snail for 2-3 days, or place in oven at 40°C for 48 hours.
  7. Air-dry the prepared golden apple snail for 3 days.
  8. Deep-fry in vegetable oil for 2 minutes. Optional: Roll the flesh of the golden apple snail in batter (cornstarch or flour with egg mixture) before final cooking.
  9. For final cooking, deep-fry again for 5 minutes or until it is crispy. Let cool before serving.
  
  *Based on the "Kibit" recipe of Ms. Corazon M. Pasion, 124 St., Baler, Aurora; modified by Mario S. Dela Cruz and Ravindra C. Joshi, Crop Protection Division, PhilRice.
  Source: SEAFDEC Asian Agriculture, Vol. 22 No. 4, July-August 2000, page 12.
  

Nutritive value of golden apple snail

Nutritive value of golden apple snail flesh per 100g

- Food energy 83 calories
- Protein 12.2 g
- Fat 0.4 g
- Carbohydrates 6.6 g
- Ash 3.2 g
- Phosphorus 61 mg
- Sodium 40 mg
- Potassium 17 mg
- Riboflavin 12 mg
- Niacin 1.8 mg
- Other food values: Vit. C, zinc, copper, manganese, and iodine

List of Fertilizer and Pesticide Authority-registered molluscicides as of 31 March 2000

EC - Emulsiflable Concentrate, F - Flowable, G - Granule, P - Powder, PEL - Pellet, WP - Wettable Powder, T - Transplanted, DS - Direct Seeded, tbsp - tablespoon.
*Based on World Health Organization, classification by hazards: 2 - moderately hazardous; 4 - unlikely to present acute hazard in normal case

References

• Dancel KT and RC Joshi. 2000. "Golden menace" in Ifugao rice terraces. SEAFDEC Asian Agriculture 22(1): 11, 12, 31-33.

• Dela Cruz MS and RC Joshi. 2001. Re-evaluation of the bioefficiency of commercial molluscicide formulations on the golden apple snail Pomacea canaliculata. Philipp. Agric. (in press).

• Dela Cruz MS, RC Joshi, and EC Martin. 2000. Potential effects of commercial molluscicides used in controlling golden apple snalts on the native snail Vivipara costata (Quoy and Gaimard). Philipp. Ent. 14(2):149-157.

• Dela Cruz MS, RC Joshi, and AR Martin. 2001. Basal application of fertilizer reduces golden apple snail population. IRRN. (in press)

• Department of Agriculture and Food and Agriculture Organization of the United Nations. 1989. A primer on integrated golden kuhol management. 26 pp.

• Joshi RC, MS Dela Cruz, GP Banawa, J Modesto, and ER Tiongco. 2000. Golden apple snail and management. In: Highland rice production in the Philippine Cordillera. Central Cordillera Agricultural Programme (CECAP), Banaue, Ifugao and Philippine Rice Research Institute (PhilRice), Maligaya, Munoz, Nueva Ecija. 155-157.

• Joshi RC, MS Dela Cruz, AR Martin, JC Cabbigat, RF Bahatan, AD Bahatan, J Choy-Awon, NP Chilagan, and AB Cayong. 2001. Current status of golden apple snail in the Ifugao Rice Terraces, Philippines. Journal of Sustainable Agriculture, USA. (in press)
  
  
• Moratto-Rejesus B, AS Sayaboc, and RC Joshi. 1988. The distribution and control of the introduced golden snail (Pomacea sp.) in the Philippines. Paper presented at the symposium on introduction of germplasm and plant quarantine procedures. Jalan Ampang, Kuala Lumpur, Malaysia. 26 pp.
  
  
• Revilla, IM. 1989. State of golden kuhol infestation in selected rice farming villages of Nueva Ecija. Paper presented during the Workshop on Golden Kuhol Management in the Philippines held at PhilRice Maligaya, Munoz, Nueva Ecija. 75 pp.
  
  
• Tanzo IR, RC Joshi, and GH Baker. 2000. Fanners' assessment of golden apple snail management options promoted in the strategic extension campaign, Philippines. Poster presented at the Molluscs 2000 conference, Sydney, Australia.
  

Acknowledgements

• Subject Matter Specialists:
  Mario S. Dela Cruz
  Ravindra C. Joshi
  Emmanuel R. Tiongco
  Anita V. Antonio
• Managing Editors:
  Diadem B. Gonzales
  Olive Rose 0. Matchoc
• Layout Artist:
  Carlo G. Dacumos
• Webpage version:
  Stijn A. Ghesquiere
• Illustrator:
  Carlito N. Bibal
• Editorial Advisers:
  Leocadio S. Sebastian
  Karen Eloisa T. Barroga

For more information, contact:
Crop Protection Division
Philippine Rice Research Institute
Maligaya, Science City of Munos, 3119 Nueva Ecija
Tel. Nos.: (044) 456-0285; -0113 local 227

Published 2001 by the Philippine Rice Research Institute. Readers are
encouraged to reproduce the contents of this bulletin with
acknowledgment.

About DA-PhilRice

The Philippine Rice Research Institute (PhilRice) is a government corporation attached to the
Department of Agriculture (DA). Executive Order 1061 approved on November 5, 1985 and
amended by EO 60 dated Nov. 7, 1986 created PhilRice to help develop high-yielding technologies
so that farmers can produce enough rice for all Filipinos. PhilRice accomplishes this mission
through research, technology promotion, and policy advocacy, which are implemented through a
network that includes 57 agencies and 104 seed centers strategically located nationwide.

Its interdisciplinary programs include the following: (1) direct-seeded and (2) transplanted
irrigated lowland rice; (3) hybrid rice; (4) rice for adverse environments; (5) rice-based farming
systems; (6) rice and rice-based products; (7) policy research and advocacy; and (8) technology
promotion and development. With these programs, PhilRice aims to develop and promote
technologies that are ecosystem-based, location- and problem-specific, and profitable to the
Filipino farmers.

Contact / more information

• DA-PhilRice Maligaya Science City of MuRoz, 3119
  Nueva Ecija
  Tel: 63 (044) 456-0113, -0258, -0277, -0285, -0354
  Tel/Fax: 63 (044) 456-0112; -0649 local 261; -0651 local 511; -0652 local 515
  e-mail: phi Irice@ mozcom. corn
  URL: http://www.philrice.gov.ph

• DA-PhilRice Los Banos UPLB Campus,
  College, 4031 Laguna
  Tel: 63 (049) 536-3631 to 33, -3635
  Tel/Fax: 63 (049) 536-3515
  e-mail: philrice@ laguna. net

• DA-PhilRice San Mateo Malasin, San
  Mateo, 3318 Isabela
  Tel: 63 (078) 664-2280, -2954
  Tel/Fax: 63 (078) 664-2953
  e-mail: philrice-isabela@digitelone.com

• DA-PhilRice Batac 17 Tabug, Batac,
  2906 llocos Norte
  Tel: 63 (077) 792-4714
  Tel/Fax: 63 (077) 792-4702
  e-mail: philrice@ILN.CSI.com.ph

• DA-PhilRice Midsayap Bual Norte, Midsayap,
  9410 North Cotabato
  Tel/Fax: 63 (064) 229-8178
  e-mail: philrice@microweb.com.ph

• DA-PhilRice Agusan Basilisa, RTRornualdez, 8611
  Agusan del Norte
  Tel: 63 (085) 818-2277, -3377; (0918)406-1145
  Tel/Fax: 63 (085) 818-4477
  e-mail: cvcesOO1@cdo.philcom.com.ph

Related pages on applesnail.net

'Apple snail eradication' section, 'Apple snails as bio-agent' section, 'Pomacea canaliculata' section.
'Apple snails as food ' section, 'Recognizing apple snails' section, 'Bibliography on the golden apple snail' section.

Links

• Apple Snails in Wetland Taro Production
  Basic info about Apple snails in Hawaii and methods to control their population.
• Some Hawaii pests arrived by invitation (article)
  Invasion of the (Pomacea) apple snail inHawaii.
• Aquatic Species Introductions Database
  Database with species introduction info. Search with "Pomacea" for apple snail spreading.
• The Parable of the Golden Snail
  A frightening story about genetical 'improved' rice seeds. The apple snail invasion in the Philippines is used here as example to warn that these new technologies are not always beneficial for the farmers. 
• Socio-economic aspects of apple snail invasion in Asia (article)
  Invasion of the (Pomacea) apple snail in the rice fields of Asia.
• Fish farming in Vietnamese rice fields fights golden apple snail pest
  Includes the methods used to control the snail population.
• Golden Apple Snail
  A radio interview about the possible invasion of the Golden Apple Snail in Australia. This snail, which is originally from South America was introduced into Asia through the aquarium trade It was then also promoted as a potential food source for humans Now it's in plague. This danger is now treatening Australia.
• Keeping predator snails at bay
  New techniques and advances in the battle against the Golden Apple Snail in South-East Asia. The results indicate that extracts from the leaves and the stem from Ximenia americana kills the snails at low dosages, while leaving other species unharmed.
• Un sudamericano invade Asia
  Article in Spanish about the invasion of Pomacea canaliculata into Asia. This article was written by María Cristina Damborenea y Gustavo Darrigran and published in CienciaHoy, Volumen 11 - Nº 66 Diciembre 2001/ Enero 2002.

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