The pests died - or did they? And so did a lot of other creatures:
Observations and reflections
August 12, 2003 An aerial applicator began spraying a large cotton field at about 1:15 PM on August 11. He finished about an hour later. For obvious reasons I will not name the owner, the applicator, or the location. Suffice it to say, it represents many similar events all through the cotton belt.
The setting: The field was irregular and elongated in shape, extending along a long road frontage in a fairly wild area. The entire field was on a very low ridge that was perhaps three feet higher than the surrounding low wetland. There was one lot carved from the field with a house and a couple trees. No one seemed to be at home. The next nearest home is at least a half mile. On the south side of the field was a pine woods on a small sandy ridge that was a bit higher than the field. The west and north side were bounded by low wetland, with scrubby regrowth hardwoods which had been clear-cut several years ago. The road ran along the east side, and opposite the field was wetland hardwoods that had been clear-cut about five years ago and were in regrowth. All observations were made on the road and the shoulder of the road. A rough guess would be that the field was around 75 acres, larger than most fields in this area.
Copyright 2003, David L. Green Unauthorized use prohibited
Observations: The plane began making passes from east to west and west to east along the south margin of the field. I observed from the west end of the road frontage. Each time the plane pulled up over the road spray could be observed to follow across the road and into the woods on the east side.
The cotton plants were in bloom and there were abundant wild flowers along the road, with honeybees and bumblebees visiting the wildflowers. Presumably they were also visiting the cotton blossoms. The most noticeable feature was the large number of dragonflies. I would estimate that there were at least 1000 dragonflies along the road frontage of this field. There were also large numbers of sulfur butterflies along the ditch. Swallowtail butterflies could also be seen sipping at the vervain and moving on. There were about a half dozen of these on the road frontage. A couple red spotted purple butterflies were also present. Gulf fritillaries were not; for some reason they have been few in number so far this year.
(This area is very familiar to me as I often walk the road. I also come here frequently to take photos of nature.)
I took a number of photos of the plane. As it worked its way toward me I was able to get some good shots. When it was about half done with the field, I rolled up my car windows and drove to the east end of the road frontage, where I took additional photos. As I was in the area already sprayed (by drift from the field) I noticed only a few dragonflies still flying. Their flight was much more erratic, and some were on the road surface obviously dying.
I left the area when the applicator moved on to another field, and returned about an hour and a half later to look at the scene and take photos. I did look briefly in the grass on the road shoulder, but it was too dense to see much, so I made most observations along the edges of the pavement, and took photos (below). I observed many dead insects. The most common were polistes wasps, but there were also bees, dragonflies, grasshoppers and moths. No dragonflies were seen alive, in stark contrast to their intense activity a few hours earlier. No bees or other insect visitors could be found on the wildflowers alongside the road except I saw one cotton bollworm adult visit Eupatorium (photo below). One beetle that I thought dead, ran for cover when I tried to photograph it.
Today (the day after spraying) I returned to the scene. It is eerily quiet, as I am used to seeing a lot of activity along this road. Not a single dragonfly was in evidence, nor any bees, nor butterflies. After watching for awhile I saw a silver-spotted skipper on the vervain. Then I saw an eastern tiger swallowtail flying through. But it did not stop.
I found the stillness disconcerting, and I went along the road, away from the field to see if I could find normal life. It was a half mile before I saw a single dragonfly. A little further and there were many. I stopped to watch awhile, relieved to see the sulfur butterflies flitting everywhere and dragonflies and bees like they had been at the cotton field the day before.
The Pesticide: On the basis of the number of insects observed killed, and my general experience of agriculture in the area, I can safely presume that it was an insecticide. Here is a list of legal materials from Clemson's recommendations. It could be any of these (presuming that it was a legal material).
The Survivors: They were four species of insects seen alive two hours after the application. One was a small white moth, fairly numerous, which I was unable to photograph or identify because it was very active and tended to hide in the grass. I strongly suspect it was a pest insect. The other was Helicoverpa zea, known as the corn earworm or the cotton bollworm. They also were quite active, but I was able to capture these blurred images of two by telephoto:
The third species seen were fire ants, which seem to be quite resistant to pesticides. They were scavenging the corpses of some of the dead insects. A fourth species, not identified, was a small beetle, which I thought was dead, but when I attempted to take a photo, it scurried for cover.
The Casualties: A number of dead or dying insects were seen along the roadside. The most common were polistes wasps. These are predators of caterpillars, which they feed to their brood. I have seen them highly active in unsprayed cotton in the past, busily searching throughout the foliage. Judging from the numbers seen in this small area, there must have been thousands of these beneficial insects killed in the field and overspray area.
Copyright 2003, David L. Green Unauthorized use prohibited
The second most common casualty was the dragonflies. These are predators upon flies and mosquitoes, and the larval forms are even more voracious predators upon larval mosquitoes in standing water. No dragonfly survivors were seen.
Also among the casualties, there were one each: honeybee, male velvet ant, cotton bollworm, katydid, and grasshopper. Since the sample size was small, there were indubitably many more of each killed. Honeybees are highly beneficial insects. No dead bumblebees were spotted, but they were conspicuous by their absence the next morning.
There are special laws pertaining to bees, which will be discussed below. Of course honeybees are one of the most beneficial insects known to mankind. Half of the US beehives are trucked each year to California for almond pollination, then most of them are used again to pollinate apples, cherries, blueberries, strawberries, seed legumes, vine crops, and many others during the rest of the season. Wild honeybees have become scarce due to parasitic mites, pesticide damage, new diseases, and changing agricultural practices, such as the decline in use of clover, buckwheat and other crops that are high in nectar yields, and the mowing of alfalfa for hay prior to bloom.
I had misidentified the insect on the right above. A good friend identifies it as a male velvet ant, Casymutilla sp. Velvet ants are parasitic upon ground nesting wasps and bees. The wingless and bright red fuzzy female is more familiar to us, as it scurries around on the ground. These "ants" are really wasps. It could be considered beneficial or a pest, depending on which species it is parasitizing.
Cotton bollworm (also called corn earworm when it is feasting on corn) and grasshoppers are considered pests. Grasshoppers are usually naturally controlled and usually are only minor pests in South Carolina. Katydids can be pests in fruit areas but are not significant pests here.
Copyright 2003, David L. Green Unauthorized use prohibited
#1. Drift To the best of my knowledge all insecticide labels prohibit allowing drift to move outside the target crop. When it goes onto another landowner's property, it is also known as chemical trespass. On this occasion spray was plainly seen passing across the road and at least a hundred feet into the woods on several passes. Specific directions from the label could be obtained if the material were known.
#2. Bee Protection Almost all insecticides, except granular or bait formulations, prohibit application while bees are foraging on flowers within the application area. The language may vary according to the residual or non-residual characteristics of the pesticide. Did the applicator check for foraging bees on flowers that are attractive to bees? Sample label statements about bees Flow chart codifying label directions
Common Flowers: Blooming within the Application Area: (including the drift area)
Of course the most common was the cotton itself (Gossypium hirsutum), with thousands of blossoms in the field. Cotton produces abundant nectar and pollen and is highly attractive to bees of many species.
||Pineland hibiscus (Hibiscus aculeatus), a relative of cotton, also is very common in the margins around the field. It is highly attractive to bees.|
||Meadow beauty (Rhexia sp.) is profuse along the margins. It is moderately attractive to bees.|
||Hempweed (Mikania scandens) was present along the margins. It is highly attractive to bees.|
||Wild vervain (Verbena bonariensis) is extremely attractive to bees and butterflies. It is profuse along the field margins.|
||Eupatorium (Eupatorium rotundifolium) was present in large quantities. This species seems to not be attractive to bees, but apparently yields nectar to cotton bollworm adults|
||Ironweed (Vernonia acaulis) is present across the road from the field, within the drift area. It is highly attractive to bees of many species.|
no photo, but photos at the link to the right
|Winged sumac (Rhus copalina) was visible along the back of the field/woods margin, but I was not able to get back to photograph it without walking across the field. It is extremely bee attractive. To see the flower and the bees that normally visit it, you can go to this link. These photos were taken about three miles from here last year at about the same time.|
Not Yet Identified:
| Neither of these flowers seemed to be of much
interest to bees. There were also cyprus vine, and sicklepod which are of little
interest to bees.
Wild morning glory was present, and it is highly attractive to bumblebees, but the blossoms were closed at the time of application, and at subsequent observations.
Prevention of Drift? It's hard to imagine how an aerial application can comply with the label requirements. The truth of the matter is that the requirements are ignored unless someone complains. For example, if someone had been home at the lone house in the field, and had called the "pesticide police" about drift, some action might be taken. Of course non-human creatures have no voice and are just simply "out in the cold" unless a human speaks up for them.
Prevention of the Bee Violations that cause bee kills? I have requested Dr. Mitchell Roof of Clemson University Extension that he train cotton scouts to monitor the hours that bees forage in the cotton. Dr. Roof's response was that it would be a good idea, but, to my knowledge, it has not been implemented. The only way violations can be prevented is for the applicator to know when bees are foraging. Once a bee kill has occurred, there is no way to truly recover the losses, including the losses of pollination that the bees normally do.
Enforcement on the Bee Violations? There is little chance of any action on the violations. South Carolina's "pesticide police" are under the jurisdiction of Clemson University, which receives grants from the corporations that produce pesticides. This is, of course, an inherent conflict of interest. Further, the officials in charge of pesticide regulation are former members of the pesticide industry.
Past experience of other violations I have reported give little hope of any enforcement. The evidence of bee kills is usually scattered throughout the spray area (wherever the bees dropped). Sometimes some bees make it back to the hives and die there, which gives the investigators some paperwork to fill out, but nothing more is done in almost every case. I have requested Dr. Von H. McCaskill, head of the Department of Pesticide Regulation do some preventive enforcement, checking on applications as they happen, asking applicators what steps they have taken to monitor bee foraging and comply with bee labels. This they are loathe to do. The standard response is that there aren't enough personnel. Of course this type of preventive enforcement is much less time consuming than doing an investigation after a bee kill.
The label directions do not specify only honeybees, just "bees," and bumblebees and other wild bees are important pollinators. Yet, curiously, Cam Lay of the SC Department of Pesticide Regulation states unequivocably (and in writing) that only honeybees are referenced in the label.
Recovery: (Third day report) In one half hour of observation, on August 13, at mid day, I saw about a dozen sulfur butterflies, three silver spotted skippers. They were foraging mainly on the cotton and vervain. One dragonfly was seen. Paying close attention to the attractive blossoms, one honeybee was seen. No other bees were observed. One polistes wasp was seen foraging, presumably for caterpillars, in a stand of goldenrod.
The beginnings of recovery were encouraging, but activity as of now is less than 5% of what it was three days ago.
Modes of Recovery: The observations above are consistant with my past experience of recovery. Adult dragonflies and butterflies are not tied to one location and can move many miles, though dragonflies tend to remain near wetland where they can reproduce, and butterflies near their preferred larval food plants.
Honeybees are tied to their nest site, but they are far ranging and have large colonies. When there is a large loss of field force honeybees lose the ability to feed themselves. The colony may seem to lose morale and go into decline and ultimately death, or it may increase brood rearing, and convert young house bees into foraging activity at an earlier age than normal. It is a time of desperation for a colony, because they are "robbing Peter to pay Paul" by taking needed nurse bees out to forage, at the same time there is a greater need for them to care for brood to replace the lost bees. Beekeepers who know their hives have been "hit" usually help the bees by feeding sugar syrup. This takes some of the pressure off them to gather feed for the brood.
Bumblebees and most solitary bees are very short ranging, and are quite tied to their nest. It will take them much longer to recover populations, because they don't move nearly as far in one season. In widespread aerial applications for mosquitoes, I have seen it take a decade to fully recover bumblebee and other native populations. Widespread aerial applications (such as mosquito control applications) make "islands of safety" fewer and farther, from which recovery populations must draw. Of course wild bees have no human assistance to recover, as do domestic honeybees.
The only surprise for me was to see a polistes wasp back so soon. They are quite short ranging, and are tied to their nesting site. Apparently this individual was "home" during the application at a nesting site that was far enough from the field to be unaffected.
A Personal Observation: Though I was careful to not get directly hit by the spray during the application, I noticed a bitter taste in my mouth, indicating that some amount of pesticide had somehow entered my body. I also am troubled with some wheezing, which I can usually control with menthol cough drops. In my earlier years I worked on farms and used a lot of pesticides. I always noticed, no matter how well protected I was, that bitter taste and the tendency to wheeze. None of this was unexpected. However I was surprised that during the third day observations, at which point the pesticide should be broken down, I still immediately got the bitter tast in my mouth and began to wheeze, simply by walking along the road in the spray area. Would it be dangerous, for say, a severe asthmatic, to drive through the application area with windows down?
The Questions That Remain?
An Editorial Comment: With all the fears about West Nile disease, and the carrier mosquitoes, we have just witnessed a massacre of dragonflies, one of the basic natural mosquito controls.
Editorial Comment #2: "Anecdotal!" some folks will sneer and dismiss this story. You betcha it's anecdotal! But when coupled with many years of observations of the same thing, it's much more than anecdotal. I have walked fields and seen dead bees by the thousands between the rows. The only difference now is that I have more tools to document what is happening.
Feedback: Anyone with a responsible answer to these questions, or comments on any other aspect of this issue is welcome to respond. Particularly good responses may be posted here; your writing to me on this issue will be assumed to be such permission, unless you state in the negative. To Respond
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