Roaches in the House
During my stay as Aquarium Supervisor of the J L Scott Aquarium in Biloxi I ran an advisory service and a fish disease/ parasite diagnostic service/ lab for the public, pet stores, other labs, aquaculture ventures, other aquariums, etc. I examined many fish, and other aquatic organisms, under many different and sometimes strange circumstances.
One time a man came in with his wife's pet goldfish, about 5 inches TL. The fish was under obvious stress, gasping, mouth open, and opercules flared. It was not eating. Its skin and fins looked ok.
I placed the live goldfish in a bucket of clean freshwater, and slowly added MS -222 ( tricaine methanesulfonate ) with small granules stuck on forceps and stirred the water with the forceps. I kept on adding MS-222 until the fish just barely started to lose equilibrium, noticed by its starting to slip from a vertical body position to laying over on its side. Then I placed it into a finger bowl with clean water so it would start reviving and examined its branchial cavity. A large American roach in a molt stage without wings yet was lodged in its branchial cavity. I disengaged the roach legs from the gill arches and pulled the roach out, and said, "Tell your wife she has roaches in the house."
The goldfish apparently tried to eat a roach that fell into its water and the roach got stuck, causing the fish a lot of stress.
The goldfish was revived in clean freshwater and the man left with his fish problem solved, but a new one to tackle.
Adrian R. Lawler, Ph.D. (C) 2012 --
Wednesday, November 28, 2012
Tuesday, November 27, 2012
Save Redfish from Amyloodinium
Save Redfish from Amyloodinium
In the 1980s I worked with another university's research team on redfish aquaculture as an advisor. This was while I was Aquarium Supervisor at the J L Scott Aquarium in Biloxi. I received a call from them to check out sick redfish in their indoor tank systems of 1000-gallon tanks with bead filters.
I could not examine the fish, so I told the staff to put the outflow of the bead filter into the tank at the edge and direct the water flow along edge so the water in the tank had a circular motion for a few minutes. Then we turned the filter off to let the water settle for a few minutes. I then had them put a siphon hose in the middle of the tank and siphon off water from the tank bottom into a bucket. I then stirred the water in the bucket in a circular motion and let it settle for a few minutes. Finally I used a pipette to draw off water from the bottom center of the bucket and looked at the debris with a dissecting stereomicroscope. After seeing what appeared to be small cysts I put the debris under a compound microscope and confirmed the cysts were from Amyloodinium ocellatum, a parasitic dinoflagellate found on the gills, fins, and skin of various saltwater fishes.
I explained to the staff what they had and that unless they followed my advice they would lose their brood stock redfish. I told them to get some large swimming pool diatom filters and put on the tanks to suck all the infective stages of the dinoflagellates out of the tanks before they could attach to the fish. Those stages remaining on the fish would mature, fall off, and then would either be sucked up as cysts or, after divisions, as infective dinospores. Then the fish would be free of Amyloodinium. Thereafter, they could leave the diatom filters on the tanks or use them periodically to keep the Amyloodinium under control.
They had no further problems with Amyloodinium. In the early 1980s I told various aquaculture ventures and public aquariums how to save their fish from Amyloodinium using diatom filters. I had already told fellow staff members the procedure to use on saving cobia, pompano, speckled trout, red snapper, striped bass, etc. from Amyloodinium at my organization.
To this day this is the easiest way to keep saltwater fish without worry from Amyloodinium.
Adrian R. Lawler, Ph.D. (C) 2012 --
Lawler, A. R. 2007. Diatom filters.
http://www.aquarticles.com/articles/management/Lawler_Diatomfilters.html
In the 1980s I worked with another university's research team on redfish aquaculture as an advisor. This was while I was Aquarium Supervisor at the J L Scott Aquarium in Biloxi. I received a call from them to check out sick redfish in their indoor tank systems of 1000-gallon tanks with bead filters.
I could not examine the fish, so I told the staff to put the outflow of the bead filter into the tank at the edge and direct the water flow along edge so the water in the tank had a circular motion for a few minutes. Then we turned the filter off to let the water settle for a few minutes. I then had them put a siphon hose in the middle of the tank and siphon off water from the tank bottom into a bucket. I then stirred the water in the bucket in a circular motion and let it settle for a few minutes. Finally I used a pipette to draw off water from the bottom center of the bucket and looked at the debris with a dissecting stereomicroscope. After seeing what appeared to be small cysts I put the debris under a compound microscope and confirmed the cysts were from Amyloodinium ocellatum, a parasitic dinoflagellate found on the gills, fins, and skin of various saltwater fishes.
I explained to the staff what they had and that unless they followed my advice they would lose their brood stock redfish. I told them to get some large swimming pool diatom filters and put on the tanks to suck all the infective stages of the dinoflagellates out of the tanks before they could attach to the fish. Those stages remaining on the fish would mature, fall off, and then would either be sucked up as cysts or, after divisions, as infective dinospores. Then the fish would be free of Amyloodinium. Thereafter, they could leave the diatom filters on the tanks or use them periodically to keep the Amyloodinium under control.
They had no further problems with Amyloodinium. In the early 1980s I told various aquaculture ventures and public aquariums how to save their fish from Amyloodinium using diatom filters. I had already told fellow staff members the procedure to use on saving cobia, pompano, speckled trout, red snapper, striped bass, etc. from Amyloodinium at my organization.
To this day this is the easiest way to keep saltwater fish without worry from Amyloodinium.
Adrian R. Lawler, Ph.D. (C) 2012 --
Lawler, A. R. 2007. Diatom filters.
http://www.aquarticles.com/articles/management/Lawler_Diatomfilters.html
Broodstock Redfish Handling Deaths at Aquaculture Facility
Broodstock Redfish Handling Deaths at Aquaculture Facility
In the l980s and l990s I was involved with several redfish aquaculture ventures in the United States as an advisor and scientist to assist them. I was a marine biologist that majored in fish parasitology/diseases under Dr. W. J. Hargis, Jr., and had extensive experience in holding, and rearing aquatic organisms. I was hired as a post-doctoral fellow by Dr. Gordon Gunter, an influence on my life and research. Part of this time as an advisor in various aquaculture projects I was Head of Experimental Organism Culture of a Toxicology Program and co-chairman of the Toxicology Program and the rest of the time I was Aquarium Supervisor of the J L Scott Aquarium in Biloxi. This was an advisory service of the state organization I was a member of during those times. We were in the initial stages of learning how to raise redfish and learned as we progressed along.
In the mid l980s one facility had built its broodstock tank and building and was ready to stock out adult redfish in order to obtain eggs. The personnel got adult redfish from a purse seine operation and transported them to a man-made pond on the grounds of the aquaculture farm. After those that were injured in capture and transport died, it was decided to be time to move the adults from the pond uphill to the holding facility.
The adult fish were coralled by pulling a seine in the pond, pulled into shallow water (where they became frantic and thrashed about), manually picked up and carried to a weighing-measuring table (they were dropped, and slime coat damaged), measured and weighed (beating tail on table, slid off table, etc.), manually carried (several tens of steps) to the brood tank, and put into tank water. I was mostly an observer/advisor during this operation as I did not want to be directly responsible, as a state employee, for the well-being of expensive fish belonging to a private venture plus I could not impose my ideas onto a private business (They could accept or reject my advice as they wished.). The owners of the redfish farm, their staff, and friends were the ones handling the operation and their procedures (which I presumed they had researched) were followed.
I had to bite my tongue on the excessive handling of the fish, and commented that they should be out of water as little as possible. For some reason they thought it necessary to get accurate readings of weight and length of the fish before they went into the brood tank. The fish were out of the water from pond to tank usually five minutes or more.
After about 35 fish were moved to the brood tank, the primary owner said he was glad that was done. I said he was not finished yet. He asked why. I told him that someone needed to get into the tank and pull out all the dead fish before they fouled the water. They did not want to believe me. The junior owner finally got down to his underwear and got into the tank, feeling around with his feet and hands. He was surprised when he found the first dead fish, and shocked when they got up to 12 dead fish. A few more died on following days.
After we had a pile of dead fish on the floor, the owners wanted to know why. I started opening them up. All 12 had bleeding from the blood vessels in the mesenteries of the digestive tract. The fish had the same problem beached whales get. When no longer supported (buoyed up) by water gravity takes over and internal organs "fall," causing ripping in the mesenteries and contained blood vessels, internal bleeding, shock, and sometimes death.
The rough handling, carrying, dropping, flopping on table, etc. caused internal bleeding and shock that some of the fish could not handle.
The owners should have transported the fish as quickly as possible to the brood tank and forgotten about weighing and measuring. They should also have carried the fish in wet slings for better body support, or in water if they could.
The facility succeeded in getting eggs from their remaining redfish, and raised redfish for several years before going out of operation.
We all learned from this .............
Adrian R. Lawler, Ph. D. (C) 2012 --
In the l980s and l990s I was involved with several redfish aquaculture ventures in the United States as an advisor and scientist to assist them. I was a marine biologist that majored in fish parasitology/diseases under Dr. W. J. Hargis, Jr., and had extensive experience in holding, and rearing aquatic organisms. I was hired as a post-doctoral fellow by Dr. Gordon Gunter, an influence on my life and research. Part of this time as an advisor in various aquaculture projects I was Head of Experimental Organism Culture of a Toxicology Program and co-chairman of the Toxicology Program and the rest of the time I was Aquarium Supervisor of the J L Scott Aquarium in Biloxi. This was an advisory service of the state organization I was a member of during those times. We were in the initial stages of learning how to raise redfish and learned as we progressed along.
In the mid l980s one facility had built its broodstock tank and building and was ready to stock out adult redfish in order to obtain eggs. The personnel got adult redfish from a purse seine operation and transported them to a man-made pond on the grounds of the aquaculture farm. After those that were injured in capture and transport died, it was decided to be time to move the adults from the pond uphill to the holding facility.
The adult fish were coralled by pulling a seine in the pond, pulled into shallow water (where they became frantic and thrashed about), manually picked up and carried to a weighing-measuring table (they were dropped, and slime coat damaged), measured and weighed (beating tail on table, slid off table, etc.), manually carried (several tens of steps) to the brood tank, and put into tank water. I was mostly an observer/advisor during this operation as I did not want to be directly responsible, as a state employee, for the well-being of expensive fish belonging to a private venture plus I could not impose my ideas onto a private business (They could accept or reject my advice as they wished.). The owners of the redfish farm, their staff, and friends were the ones handling the operation and their procedures (which I presumed they had researched) were followed.
I had to bite my tongue on the excessive handling of the fish, and commented that they should be out of water as little as possible. For some reason they thought it necessary to get accurate readings of weight and length of the fish before they went into the brood tank. The fish were out of the water from pond to tank usually five minutes or more.
After about 35 fish were moved to the brood tank, the primary owner said he was glad that was done. I said he was not finished yet. He asked why. I told him that someone needed to get into the tank and pull out all the dead fish before they fouled the water. They did not want to believe me. The junior owner finally got down to his underwear and got into the tank, feeling around with his feet and hands. He was surprised when he found the first dead fish, and shocked when they got up to 12 dead fish. A few more died on following days.
After we had a pile of dead fish on the floor, the owners wanted to know why. I started opening them up. All 12 had bleeding from the blood vessels in the mesenteries of the digestive tract. The fish had the same problem beached whales get. When no longer supported (buoyed up) by water gravity takes over and internal organs "fall," causing ripping in the mesenteries and contained blood vessels, internal bleeding, shock, and sometimes death.
The rough handling, carrying, dropping, flopping on table, etc. caused internal bleeding and shock that some of the fish could not handle.
The owners should have transported the fish as quickly as possible to the brood tank and forgotten about weighing and measuring. They should also have carried the fish in wet slings for better body support, or in water if they could.
The facility succeeded in getting eggs from their remaining redfish, and raised redfish for several years before going out of operation.
We all learned from this .............
Adrian R. Lawler, Ph. D. (C) 2012 --
Saturday, November 24, 2012
Potential Aquaculture Problems with Cobia
Potential Aquaculture Problems with Cobia
(This summary was first written 18 Nov 1997 for a potential aquaculture article. It was based on personal experience working with cobia at a research project in Ocean Springs and on display at the J L Scott Aquarium in Biloxi, Mississippi. It was recently found in an old email account and a few changes were made for this publication.)
FISH TB (Mycobacterium marinum)
Susceptible to fish TB. Signs of this disease in cobia are obvious: the fish lose normal gray/black and white markings and become very pale, with a whitish body film/sheen that even covers the eyes, which may appear bloodshot. Fins may also appear pink in color. Since cobia are voracious feeders one must take care that fish fed to them do not carry fish TB. See history of salmon culture where salmon were infected with fish TB after they were fed their dead tank-mates. Due to the dangers of fish TB a pelleted food for cobia should be developed (as they did for salmon).
INGEST SUBSTRATE
Young cobia, at least, do not distinguish between sinking food pellets and crushed coral substrate, or accidentally ingest the coral along with the food pellets, or cannot separate food from coral. See Lawler (1995). Ingestion of substrate can result in impacted intestinal tracts and lost fish. Feed floating pellets or pieces of natural food, or avoid use of substrate in your system.
VORACIOUS FEEDERS
In an Aquarium setting, cobia have been observed to be one of the fastest-growing fish. In our experience, redfish, tripletail, and black drum follow cobia in growth rate. Dolphin (the fish) have one of the fastest growth rates of fishes. One of our cobia grew from about 10 lbs to almost 65 lbs in 28 months (Aug 16, 1988 to Dec 15, l990). Since cobia are voracious feeders and compete vigorously for food one must be aware of three observations made thus far:
1. Cobia can eat so much they can die ( In an aquarium setting I had 3 cobia that darted around tank rapidly, getting as much food as possible. One day after we tried to get food to other fish in the tank by throwing a lot of food into the tank, all three cobia ate a lot, and two were shortly found dead from overeating.) Solution: disperse food over surface of the tank several times a day so they do not ingest too much food at one time.
2. In their feeding frenzy cobia may collide or hit objects in the tank, resulting in internal bleeding and loss of fish. (See Lawler, 1995).
3. Cobia are voracious feeders. I call them the "pigs of the sea" because they will eat almost anything: hardhead catfish, stingrays, eels, crabs, fish, etc. When we were testing our now patented fish attractant, we had a cobia swim up to the stern of the boat and grab the test chum bag containing the attractant.
This habit of eating about anything can result in injury to the fish. In taking internal organ samples at a cobia fishing tournament, it was noticed that spines from catfish and stingrays can penetrate the gut wall and then penetrate various organs: liver, pancreas, spleen. One should probably avoid feeding "spiny" foods to cobia. Some stomachs were noticed to be devoid of food, but contained many spines.
AMYLOODONIUM INFECTION
Cobia are highly susceptible to Amyloodinium ocellatum. See papers by Lawler. Fish will have difficulty in breathing and may rest on the bottom more than normal. Isolate in a treatment tank, use 1.6 grams of Marex per 50 gallons of tank water for 13-18 hours to knock Amyloodinium off. May need more treatments because Amyloodinium caught in gill mucus can re-infect fish. In working with a chief scientist on a cobia project several years ago, I set the protocols at that lab for treatment of cobia for Amyloodinium. One can also use a diatom filter to filter infective dinospores out of the tank water and thus avoid fish loss due to Amyloodinium (see my article on diatom filters).
MONOGENETIC TREMATODE INFECTION
Cobia carry a gill monogenea Dioncus rachycentris Hargis, l955 , which, in tank/confined areas can multiply very rapidly, causing extreme breathing distress in the fish, which must then be given 1:4000 formalin baths of at least 15 minutes duration to knock most of the worms off the gills. This bath may have to be repeated several times as worm eggs in the gill mucus can re-infect the fish. Worm eggs in the water column can be filtered out with a diatom filter.
INTERNAL BLEEDING/MOVING INJURY
From personal experience in moving large redfish, one should take care in moving brood stock cobia, or any large cobia. When no longer supported by water, the forces of gravity take over and "falling" or shifting internal organs can stretch the supporting mesenteries, leading to bleeding from the blood vessels of the mesenteries, and sometimes resulting in shock and death.
Adrian R. Lawler, Ph.D. (C) 2012 --
Lawler, A.R. 1995. Some unusual deaths of cobia, Rachycentron canadum, in display tanks. Drum & Croaker 26 (Feb 1995): 9-10.
Lawler, A. R. 2007. Diatom filters. http://www.aquarticles.com/articles/management/Lawler_Diatomfilters.html
(This summary was first written 18 Nov 1997 for a potential aquaculture article. It was based on personal experience working with cobia at a research project in Ocean Springs and on display at the J L Scott Aquarium in Biloxi, Mississippi. It was recently found in an old email account and a few changes were made for this publication.)
FISH TB (Mycobacterium marinum)
Susceptible to fish TB. Signs of this disease in cobia are obvious: the fish lose normal gray/black and white markings and become very pale, with a whitish body film/sheen that even covers the eyes, which may appear bloodshot. Fins may also appear pink in color. Since cobia are voracious feeders one must take care that fish fed to them do not carry fish TB. See history of salmon culture where salmon were infected with fish TB after they were fed their dead tank-mates. Due to the dangers of fish TB a pelleted food for cobia should be developed (as they did for salmon).
INGEST SUBSTRATE
Young cobia, at least, do not distinguish between sinking food pellets and crushed coral substrate, or accidentally ingest the coral along with the food pellets, or cannot separate food from coral. See Lawler (1995). Ingestion of substrate can result in impacted intestinal tracts and lost fish. Feed floating pellets or pieces of natural food, or avoid use of substrate in your system.
VORACIOUS FEEDERS
In an Aquarium setting, cobia have been observed to be one of the fastest-growing fish. In our experience, redfish, tripletail, and black drum follow cobia in growth rate. Dolphin (the fish) have one of the fastest growth rates of fishes. One of our cobia grew from about 10 lbs to almost 65 lbs in 28 months (Aug 16, 1988 to Dec 15, l990). Since cobia are voracious feeders and compete vigorously for food one must be aware of three observations made thus far:
1. Cobia can eat so much they can die ( In an aquarium setting I had 3 cobia that darted around tank rapidly, getting as much food as possible. One day after we tried to get food to other fish in the tank by throwing a lot of food into the tank, all three cobia ate a lot, and two were shortly found dead from overeating.) Solution: disperse food over surface of the tank several times a day so they do not ingest too much food at one time.
2. In their feeding frenzy cobia may collide or hit objects in the tank, resulting in internal bleeding and loss of fish. (See Lawler, 1995).
3. Cobia are voracious feeders. I call them the "pigs of the sea" because they will eat almost anything: hardhead catfish, stingrays, eels, crabs, fish, etc. When we were testing our now patented fish attractant, we had a cobia swim up to the stern of the boat and grab the test chum bag containing the attractant.
This habit of eating about anything can result in injury to the fish. In taking internal organ samples at a cobia fishing tournament, it was noticed that spines from catfish and stingrays can penetrate the gut wall and then penetrate various organs: liver, pancreas, spleen. One should probably avoid feeding "spiny" foods to cobia. Some stomachs were noticed to be devoid of food, but contained many spines.
AMYLOODONIUM INFECTION
Cobia are highly susceptible to Amyloodinium ocellatum. See papers by Lawler. Fish will have difficulty in breathing and may rest on the bottom more than normal. Isolate in a treatment tank, use 1.6 grams of Marex per 50 gallons of tank water for 13-18 hours to knock Amyloodinium off. May need more treatments because Amyloodinium caught in gill mucus can re-infect fish. In working with a chief scientist on a cobia project several years ago, I set the protocols at that lab for treatment of cobia for Amyloodinium. One can also use a diatom filter to filter infective dinospores out of the tank water and thus avoid fish loss due to Amyloodinium (see my article on diatom filters).
MONOGENETIC TREMATODE INFECTION
Cobia carry a gill monogenea Dioncus rachycentris Hargis, l955 , which, in tank/confined areas can multiply very rapidly, causing extreme breathing distress in the fish, which must then be given 1:4000 formalin baths of at least 15 minutes duration to knock most of the worms off the gills. This bath may have to be repeated several times as worm eggs in the gill mucus can re-infect the fish. Worm eggs in the water column can be filtered out with a diatom filter.
INTERNAL BLEEDING/MOVING INJURY
From personal experience in moving large redfish, one should take care in moving brood stock cobia, or any large cobia. When no longer supported by water, the forces of gravity take over and "falling" or shifting internal organs can stretch the supporting mesenteries, leading to bleeding from the blood vessels of the mesenteries, and sometimes resulting in shock and death.
Adrian R. Lawler, Ph.D. (C) 2012 --
Lawler, A.R. 1995. Some unusual deaths of cobia, Rachycentron canadum, in display tanks. Drum & Croaker 26 (Feb 1995): 9-10.
Lawler, A. R. 2007. Diatom filters. http://www.aquarticles.com/articles/management/Lawler_Diatomfilters.html
Wednesday, November 21, 2012
Dolphin Deaths in the Gulf
Dolphin Deaths in the Gulf
The SunHerald of 16 November 2012 reported some dolphin deaths in the Gulf, http://www.sunherald.com/2012/11/16/4309592/hunt-is-on-for-dolphin-killers.html#storylink=relast , and an investigator was appointed http://www.sunherald.com/2012/11/20/4315408/noaa-appoints-investigator-to.html .
I am guessing that some dolphins that learned how to get a free lunch from those working on the water by making a hole in their nets and eating their catch were "discouraged" from stealing by a few bullets. It is difficult to discourage dolphins, people, and various other animals once they have learned how to get a free lunch at someone else's expense.
I also suspect the dolphin that got its lower jaw ripped off/cut off (?) got it caught in the net while trying to steal some catch, and the net was pulled in, tearing jaw off. Or the dolphin struggled so much to get loose (before it drowned) it tore its own jaw off and bled to death. Or the jaw was cut off after the dolphin drowned to remove it from the net. This one was probably an accident.
The one with tail cut off could be due to tail getting caught in lines of net or net itself and it then drowned. Then it could have been cut loose and out of net tangle. This one was also probably an accident.
Dolphins sometimes drown when caught in nets and getting tangled up.
If we could somehow figure out a way to compensate those working on the water for net damage and loss of catch from dolphins eating catch or catch escaping out net holes the "discouraging" of stealing would probably stop.
Adrian R. Lawler, Ph.D. (C) 2012 --
The SunHerald of 16 November 2012 reported some dolphin deaths in the Gulf, http://www.sunherald.com/2012/11/16/4309592/hunt-is-on-for-dolphin-killers.html#storylink=relast , and an investigator was appointed http://www.sunherald.com/2012/11/20/4315408/noaa-appoints-investigator-to.html .
I am guessing that some dolphins that learned how to get a free lunch from those working on the water by making a hole in their nets and eating their catch were "discouraged" from stealing by a few bullets. It is difficult to discourage dolphins, people, and various other animals once they have learned how to get a free lunch at someone else's expense.
I also suspect the dolphin that got its lower jaw ripped off/cut off (?) got it caught in the net while trying to steal some catch, and the net was pulled in, tearing jaw off. Or the dolphin struggled so much to get loose (before it drowned) it tore its own jaw off and bled to death. Or the jaw was cut off after the dolphin drowned to remove it from the net. This one was probably an accident.
The one with tail cut off could be due to tail getting caught in lines of net or net itself and it then drowned. Then it could have been cut loose and out of net tangle. This one was also probably an accident.
Dolphins sometimes drown when caught in nets and getting tangled up.
If we could somehow figure out a way to compensate those working on the water for net damage and loss of catch from dolphins eating catch or catch escaping out net holes the "discouraging" of stealing would probably stop.
Adrian R. Lawler, Ph.D. (C) 2012 --
Thursday, November 15, 2012
Danger in Caterpillar Poo?
Danger in Caterpillar Poo?
This fall of 2012 I have been having the worse time ever with larval moths eating up my leaf lettuce, mostly deer tongue lettuce. Green caterpillars and brown caterpillars have been caught in the lettuce thus far.
A study of the internet suggested that the green caterpillars are lettuce loopers, which look similar to inchworms, and turn into moths. The brown ones appear to be corn earworms, which eat on various garden plants, and also turn into moths.
One can track their presence by looking for their poo (frass) deposited on the lettuce leaves during the night.
After eating a batch of lettuce in a salad recently I came down with an upset stomach and loose stools, apparently from bacteria in the caterpillar poo (frass). I think I did not wash the lettuce well enough.
I think it possible that caterpillar poo presents a danger to those eating raw lettuce, spinach, greens, and other vegetables if not washed well enough. This type of poo could join human poo, deer poo, and various other animal poos deposited in fields of vegetables eaten raw by humans as a possible danger of human intestinal infection. Hopefully scientists will identify the bacteria in caterpillar poo and confirm/deny if there is a potential danger to humans in caterpillar poo.
Adrian R. Lawler, (C) 2012 --
This fall of 2012 I have been having the worse time ever with larval moths eating up my leaf lettuce, mostly deer tongue lettuce. Green caterpillars and brown caterpillars have been caught in the lettuce thus far.
A study of the internet suggested that the green caterpillars are lettuce loopers, which look similar to inchworms, and turn into moths. The brown ones appear to be corn earworms, which eat on various garden plants, and also turn into moths.
One can track their presence by looking for their poo (frass) deposited on the lettuce leaves during the night.
After eating a batch of lettuce in a salad recently I came down with an upset stomach and loose stools, apparently from bacteria in the caterpillar poo (frass). I think I did not wash the lettuce well enough.
I think it possible that caterpillar poo presents a danger to those eating raw lettuce, spinach, greens, and other vegetables if not washed well enough. This type of poo could join human poo, deer poo, and various other animal poos deposited in fields of vegetables eaten raw by humans as a possible danger of human intestinal infection. Hopefully scientists will identify the bacteria in caterpillar poo and confirm/deny if there is a potential danger to humans in caterpillar poo.
Adrian R. Lawler, (C) 2012 --
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