methods such as pits and screens were also employed to collect hoppers.  Sodium arsenite, with and without bait, was the dominant insecticide used from the early 1920's to mid-1940's, with benzene hexachloride and subsequently its gamma isomer (lindane) being dominant from then into the 1980's.

During the most recent outbreak, government locust control costs for the financial year April 1985 to March 1986 totaled 28.1 million Rand (=U.S. $11.24 million).  The major costs were for insecticides (R17 million) and subsidy of private vehicles used for control work (R4.9 million).  Other control costs included wages to non-government personnel, government transport costs, hire of aircraft (crop sprayers for locust control), and fuel and repair to equipment.  As part of the campaign to combat the locusts, the South African Defence Force put national servicemen into the field.  Ledger states that "During the winter months of 1986 the locusts rested, the Department of Agriculture marshalled its forces, and environmentalists huffed and puffed about the excess of insecticides strewn over the veld, the need for ecological studies of the brown locust and alternative control measures that should be tried."

Dr. Ledger describes with humor the clash of viewpoints that emerged during a "Workshop on Evaluation of the Locust Campaign" held in Pretoria in March, 1987.  It was hosted by the Department of Agriculture, but included a mix of outsiders, e. g., academics, chemical industry, environmentalists and farm-

ers' representatives who "did not restrain themselves from offering critical opinions on many aspects of the 'locust campaign". The Space limits our recap to the following excerpt regarding harvest possibilities:

 The man in the street reads about locusts used for animal feed and for human consumption and wonders whether any potential for locust control could be found in the intensive harvesting of the insects.  African tribes have always utilized locusts for food and the famous South African writer and epicure, C. Louis Leipoldt, included a recipe in his Cape Cookery book. . . .The logistics of locust harvesting are formidable, but serious thought is being given to the harvesting of krill in the Antarctic, where the problems and severe weather conditions pose far greater constraints than in the Karoo!
 During discussion time, the idea of locust-harvesting was dismissed as a nice thought by well-meaning city-dwellers, but totally impractical and of no real meaning in locust control.  "Not so," said Harold Braack, Warden of the Karoo National Park near Beaufort West.  He described experimental work to collect locusts with industrial vacuum cleaners, which worked very well.  The locusts were sent to an animal feed company in Cape Town which processed them, turned them into pellets and sent them back to the Karoo where farmers fed them to sheep with good preliminary results, indicating high nutritional value.

Relative to the use of vacuum devices for harvest, T. Braack et al. (1987, African Wildlife 41(4):211) note that they must be used after the hoppers, or adult fliers as the case may be, have settled and clustered for the night on vegetation. The locusts are too active and skittish to be approached during the day.

Several efforts to build a mechanical "bug catcher" have come to our attention during the past year.  The motivating force in the two most sophisticated efforts is the need to reduce the use of pesticides wherever possible, but the development of such equipment is also of interest for the possible large-scale harvest of insects as food and animal feed.  The so-called "Bug Vac" was developed specifically to deal with lygus bugs in California strawberry fields.  Strawberry growers currently spend about $90 million per year on pesticides.  The Bug Vac is basically a system of hydraulically-driven vacuum fans and suction hoses mounted on a tractor.  It covers four rows at a time and currently costs $17,000 to $20,000 per machine.  Interestingly, Bug Vac is a "selective predator;" it sucks up the lygus bugs which live on new berries high on the plant while leaving largely untouched the riper fruit and beneficial insects, including ladybugs, which live deeper inside the plant foliage.  The lygus bugs are pulverized and spit out as mulch.

The "Father of the Bug Vac" is Ed Show, a University of California-Davis graduate and, since 1972, a research entomologist with Driscoll Strawberry Associates.  Also involved is Tim Driscoll, president of Escalon Berry Farm, who managed 500 acres with Bug Vac (three of them) in 1988 and will expand that to 1,000 acres in 1989.  According to Driscoll, Bug Vac in combination with IPM (integrated pest management) has reduced chemical expenses by 75% and already has paid for itself. Show will have two dozen new model machines in the field this year and thinks the concept may spread to lettuce and broccoli which have insect problems similar to those of strawberries.  More information on the Bug Vac can be had by consulting the article by R. S. Street in Agrichemical Age 33(3):38-39, 1989.

Working from the opposite coast is the "Beetle Eater," designed in Massachusetts by Jimmy Szynal for use in potato fields.  The interesting thing about the Beetle Eater, which was described in a recent issue of Farm Show*, is that Szynal found that suction

alone was not enough to dislodge the insects which were under leaves or well down in the plant.  Thus, the Beetle Eater has both blowing and sucking power.  Air traveling at about 300 mph as it comes out of the blower tubes blasts up under the plants, and, as the insects are dislodged, they are sucked into a vacuum tube, pulverized by the fan blades and blown back onto the field.  The machine requires only a 60-hp tractor.  The Beetle Eater, unlike the Bug Vac, is not selective.  Szynal estimates that it gets 85% to 90% of all the insects in the crop, and he says, "We think it'll compete effectively with chemicals in many different crops... . Interest has been tremendous by everyone who's seen it work." More information can be had by contacting James Szynal, 88 N. Main Street, Florence, Massachusetts, 01060, USA.

                                                                                          SEE "Bug Catcher", p. 6







We want to thank Warren Rush (US AID) for a copy of this Unclassified Department of State Incoming Telegrwn, dated July, 1986:

Subject:    Locust and grasshopper treat - Burundi.... Criquet migrateur [migratory locusts] began entering Burundi in May and June from Tanzania on the east They are now to be found in Ruyigi, Kankuzo, Muyinga, Ngozi, and Kayanza Provinces.  No alarming damage has been reported to date.  The only defensive measures reportedly taken to date by local residents in affected areas has been to gather them up and eat them.

Easy availability has made the yellow mealworm, Tenebrio molitor Linn. (Family Tenebrionidae), one of the insects most commonly recommended for inclusion in recipes in the West (see recipe, p. 3).  It has been valued and reared by zoos, aquaria, etc. as food for birds, fish, and a variety of small animals since at least the 17th Century (Cotton 1929, USDA Tech.  Bull.  No. 95, and others).  The larva of another tenebrionid, the confused flour beetle, Tribolium confusum du Val, is also sometimes suggested for use in recipes, although less often.

Tenebrionids have a bad reputation, and deservedly so, as pests of meal and flour and other stored and packaged cereal foods.  As opposed to merely aesthetic reasons for rejecting insects or insect parts in food, tenebrionid-infested food products may represent a true toxicological hazard to the consumer.  It is important for this reason to note that it is the adult beetles, not the larvae, that pose the problems.

Ladisch et al. (1967, Nature 215:939-940,, 1968, Proc.  Pa. Acad.  Sci. 42:87-91, and earlier publications by this group) reported benzoquinone secretions from the adult beetles of all of several genera and species of Tenebrionidae tested, and experimental results with mice suggested that these compounds are both acutely toxic and carcinogenic.  Wirtz and Fruin (1982, J. Food Protect. 45:1084-1086) reported mutagenicity, using the Drosophila melanogaster sex-linked recessive lethal test.  Wirtz et al. (1978, Comp.  Biochem.  Physiol. 6IB:25-28) found very low concentrations in newly eclosed adults of Tribolium confusum and T. castaneun (Herbst) (<2.0 ug/insect), but that each 30-day adult could probably contribute 35-46 g p-benzoquinone to infested commodity.  Flour merely exposed to quinone vapors binds 350 ppm of it within 60 min according to Ladisch (1965, Proc.  Pa.  Acad.  Sci. 39:36).  In addition to quinones, Howard et al. (1986, Insect Biochem. 16:757-760) and Howard and Mueller (1987, J. Chem Ecol. 13:1707-1723) have recently reported that Triboliwn adult secretions (from T.

castaneum and T. brevicornis (LeC.)) contain ketones that are potent inhibitors of insect and mammalian prostaglandin synthetases.  Prostaglandins are local cell hormones which, in vertebrates, have been shown to modulate adenylate cyclase activity and facilitate ion transport, nerve transmission, platelet aggregation, and gastrointestinal function.

From the foregoing it seems apparent that tenebrionid larvae reared as food should be allowed no contact with the adult beetles or with flour or meal previously infested by them.  Ladisch et al. (1967) found a distinctly lower quinone concentration in the ebony strain of T. confusum (ave. of 2.4 g/insect) than in the wild type (57.8 g/insect), but bread baked from flour previously infested with the ebony strain was found by Smith et al. (1971, J. Stored Prod.  Res. 6:307-316) to have a distinctly offensive taste and odor.  Whether T. confusum larvae reared in such flour would be similarly affected is uncertain as there appears to be no pertinent experimental data.

Quinones appear to be much less a problem in Tenebrio molitor than in Tribolium confusum.  Ladisch et al. (1967) state that quinones were detected in T. molitor adults, but they give no data on concentration, which suggests that the concentration was probably lower than that detected in the ebony strain of T. confusum Smith et al. (1971) state that they have encountered no evidence in the literature that Tenebrio molitor causes any adverse effects on the taste or baking qualities of flour or other food products.  In fact, they reported that in bread baked from flour previously infested by T. molitor larvae, certain properties such as volume, evenness of bake, and aroma exceeded that of the controls!

Additional comment or longer contributions are invited on this subject and on the general subject of toxicological and allergenic hazards posed by insect defensive secretions and sequestered chemicals in insect families that include edible species.

"Bug Catcher"
from page five

We have no information on the weight of lygus bugs per 100 acres of California strawberries or of potato beetles and their larvae per 100 acres of potatoes.  The mass of insects obtainable in either instance is probably too low to warrant bagging them for use as high-protein chicken feed, even as a spin-off benefit.

from running a piece of heavy equipment through a cultivated crop.  The interesting point is that people are attempting to develop mechanical harvesters as one way of reducing pesticide application.  Similar thinking applied to some larger insect pests, and especially those that aggregate in nature, such as migratory locusts, Mormon crickets, and armyworms, might indeed yield multiple benefits from a single expenditure of fossil-fuel energy: crop protection, reduced pesticide use and a food or animal feed product.  People of non-European origin have frequently applied this principle on their own, using

muscle energy (see DeFoliart 1989, Bull.  Entomol.  Soc.  Am. 35:22-35, for a recent example in Thailand).  There is no readily apparent reason why the use of western technology should automatically invalidate the principle.

According to D. L. Gunn (1960, Ann.  Rev.  Entomol. 5:279300), the individuals in a single swarm of Schistocerca locusts in Africa can weigh up to 30,000 metric tons.  Food that flies or hops, on this scale, would probably overwhelm the local muscle generated harvest capability in most localities insofar as any effective crop protection is concerned.  Thus there could be a great future for someone who wants to play with the problem of developing a better Bug Vac or Beetle Eater - one that is light, highly mobile and adapted for sucking clustered locusts from their nightly resting places.

*The article from FarmShow was sent in by Milton Bliss of Hartford, Wisconsin, USA