Field Tests of Dry Baiting against the Desert Locust, Schistocerca gregaria (Forsk.)

1952 ◽  
Vol 42 (4) ◽  
pp. 675-690 ◽  
Author(s):  
D. L. Gunn
Keyword(s):  
Schistocerca Gregaria ◽  
Field Tests ◽  
Field Trials ◽  
Peanut Flour ◽  
Desert Locust ◽  
Complete Destruction ◽  
Marching Bands ◽  
Benzene Hexachloride ◽  
The Cost ◽  
Mammalian Toxicity

Field trials in British Somaliland and in the Anglo-Egyptian Sudan showed that dry bran bait can be used for complete destruction of Desert Locust hoppers (Schistocerca gregaha). Wet bait was never found to be completely effective when dry bait was ineffective.Failures of dry baiting were found which were attributable to several causes : hoppers not feeding just before moulting ; ground too hot for hoppers to remain on it ; too low or too patchy a deposit of bait ; adult locusts probably not making contact with bait. None of these failures could be attributed to the bait being dry.The main constituent of standard bait, wheat bran, should not be replaced by barley husks or peanut flour, but dom flour could be used and dura and maize flours could be tried instead of bran.The use of dry bait makes it convenient and practical for locust scouts who use camels, vehicles, etc. to destroy small bands of hoppers as soon as they find them.Dry baiting against marching bands and ring baiting can be done very conveniently and speedily by means of the Shendi Funnel, designed to be tied to the back of a vehicle.Area baiting can be done rapidly by blowing dry bait up from a dusting machine, so that the wind spreads it. An area-dosage of 25 lb./acre is recommended, and a rate of ½-acre/minute should be readily achieved.The amount of labour required is reduced to about 25% by the use of dry bait instead of wet. Dry baiting by machine uses only 10 per cent. of the labour required for dry-baiting by hand, but the cost would not fall as much as this, because higher wages would have to be paid for the greater skill necessary.Adults can be killed by baiting, but it is much more difficult than with hoppers to ensure that the locusts make contact with the bait.The insecticides already in use against the Desert Locust, arsenic and benzene hexachloride, can completely destroy hoppers when applied in bait. An insecticide is required with a long persistence like that of arsenic and a low mammalian toxicity like that of BHC.

scholarly journals Biological, technical, and social aspects of applying electrified fladry for livestock protection from wolves (Canis lupus)

2010 ◽  
Vol 37 (8) ◽  
pp. 708 ◽  
Author(s):  
N. J. Lance ◽  
S. W. Breck ◽  
C. Sime ◽  
P. Callahan ◽  
J. A. Shivik
Keyword(s):  
Canis Lupus ◽  
Food Resource ◽  
Field Tests ◽  
Field Trials ◽  
Costs And Benefits ◽  
Field Methods ◽  
In Captivity ◽  
The Cost ◽  
Study Participants ◽  
Psychological Benefit

Context. Wolf predation on livestock can cause economic hardship for livestock producers as well as reduce tolerance for wolves. Lethal control of wolves is often controversial; thus, development of effective non-lethal methods for reducing wolf–livestock conflict is important. Electrified fladry is a new tool that is similar to fladry (i.e. a barrier system that scares wolves), but electrified fladry also incorporates an electric shock designed to decrease the potential for wolves to habituate to the barriers. Aim. Evaluation of electrified fladry requires understanding of its effectiveness relative to fladry and the costs and benefits of applying it in the field. Methods. By using captive wolves, we compared the effectiveness of electrified fladry v. fladry for protecting a food resource during 2-week trials. We then performed a field trial with electrified fladry for managing wolves in Montana, USA. We measured livestock depredation and wolf activity on six treatment and six control pastures, calculated the cost of installation and maintenance, and surveyed all study participants about application of electrified fladry. Key results. We found electrified fladry 2–10 times more effective than fladry at protecting food in captivity and that hunger increased the likelihood of wolves testing fladry barriers. In field trials, we installed 14.0 km of EF systems in treatment pastures and detected wolves twice in control pastures but never in the treatment pastures. No livestock were killed by wolves in treatment or control pastures. A completed electrified fladry system cost $2303 for the first km and $2032 for each additional km, and required 31.8 person-hours per kilometre to install. We observed 18 failures (i.e. electrified system stopped working) during a total of 394 days of use. In total, 83% of ranchers who used fladry would continue to use it under certain conditions, indicating some psychological benefit to users. Conclusions and implications. The present study has demonstrated that electrified fladry offers superior protection compared with non-electrified fladry; however, further field tests are warranted to help determine whether benefits outweigh costs.

A comparison of nutritional regulation in solitarious- and gregarious-phase nymphs of the desert locust Schistocerca gregaria

2002 ◽  
Vol 205 (1) ◽  
pp. 121-129 ◽  
Author(s):  
S. J. Simpson ◽  
D. Raubenheimer ◽  
S. T. Behmer ◽  
A. Whitworth ◽  
G. A. Wright
Keyword(s):  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Nutritional Regulation ◽  
Body Protein ◽  
Genetic Potential ◽  
Trade Offs ◽  
Nutrient Utilisation ◽  
Two Phases ◽  
Unbalanced Diet ◽  
The Cost

SUMMARY Nutritional regulatory responses were compared for the cryptic ‘solitarious’ and the conspicuously coloured, aggregating ‘gregarious’ phases of the desert locust Schistocerca gregaria. The desert locust has the genetic potential to exist in either phase, changing between them within a lifetime and epigenetically across generations. Our aim was to compare final-instar nymphs of the two phases with respect to key nutritional variables, including (i) points of regulated intake (the ‘intake target’) for protein and carbohydrate, (ii) the nature of trade-offs between over-eating nutrients in excess and under-eating those in deficit when fed nutritionally unbalanced foods, (iii) diet-related patterns of nutrient utilisation, and (iv) the performance consequences of eating nutritionally unbalanced diets. When provided with pairs of nutritionally unbalanced but complementary foods, both phases regulated their intake of protein and carbohydrate to a similar point. However, when confined to foods that were of unbalanced protein to carbohydrate ratio, gregarious nymphs ate more than solitarious insects. Both phases regulated protein growth, but gregarious insects did so to a lower adult body protein content and converted ingested protein to growth less efficiently. When fed a food high in carbohydrate and low in protein, gregarious nymphs deposited more body lipid and survived less well than did solitarious insects. Solitarious nymphs developed more quickly than gregarious nymphs except on the two most extremely unbalanced diets, on which development time was similar. The results are discussed with respect to the different nutritional ecologies of the two phases and used to develop the hypothesis that animals have evolved to trade-off the cost of eating excess of a nutritionally unbalanced diet against the probability of encountering foods of complementary composition in the future.

Observations on the effects of γ-radiation on eggs of the desert locust, Schistocerca gregaria (Forsk.)

1966 ◽  
Vol 56 (4) ◽  
pp. 725-735 ◽  
Author(s):  
P. Hunter-Jones ◽  
P. T. Haskell
Keyword(s):  
Schistocerca Gregaria ◽  
Lethal Dose ◽  
Domestic Animal ◽  
Nuclear Radiation ◽  
Desert Locust ◽  
Insecticide Treatment ◽  
Γ Radiation ◽  
Locust Control ◽  
Tissue Recovery ◽  
The Cost

It has been suggested that nuclear radiation might be used for locust control, but insufficient knowledge has hitherto been available to decide whether such a measure is feasible. In this paper, the results of some laboratory experiments on the effect of γ-radiation on eggs of the desert locust, Schistocerca gregaria (Forsk.), are described.After a single dose of γ-radiation, the resulting mortality among the eggs was correlated with the size of the dose received and the age of the egg at the time of irradiation. The dose of radiation required to kill the older eggs was 40 times greater than that required to kill young eggs; thus, a dose of 144 rads caused almost complete inviability among eggs deposited one or two days before irradiation, but a dose in excess of 5,500 rads was required to kill eggs deposited eleven days earlier. For comparison, the lethal dose of γ-radiation for humans is estimated to be 400–700 rad.When the irradiation dose was applied in three small fractions, with intervals between them, the percentage of eggs killed was less than when the same total dose was given in one exposure. This difference was presumably due to tissue recovery during the inter-radiation periods. The temperature to which the eggs were exposed during the inter-radiation periods also affected survival, recovery being greater at higher temperatures.The possibility of using γ-radiation to control locust egg-fields, the cost of the equipment needed and the hazards involved are discussed. It is concluded that control by this method not only offers no advantage in terms of cost, effectiveness or convenience as compared with conventional insecticide treatment but would be very impractical and dangerous to operators and the inhabitants, human and domestic animal, of the treated area. It is possible that other control techniques utilising radiation, such as sterile-male release or attractant traps treated with a sterilant, may be useful against certain species of locusts after further work on the development of chemical attractants has been carried out.

Control of Helicoverpa zea in Tomatoes with Chlorantraniliprole Applied Through Drip Chemigation

2010 ◽  
Vol 11 (1) ◽  
pp. 21 ◽  
Author(s):  
Thomas P. Kuhar ◽  
James F. Walgenbach ◽  
Hélène B. Doughty
Keyword(s):  
North Carolina ◽  
Helicoverpa Zea ◽  
Field Trials ◽  
Single Application ◽  
Beneficial Arthropods ◽  
Worker Exposure ◽  
Anthranilic Diamide ◽  
Mammalian Toxicity ◽  
Tomato Fruitworm ◽  
Reduced Risk

Chlorantraniliprole (=Rynaxypyr) is a novel anthranilic diamide insecticide that is of interest to vegetable growers because of its low mammalian toxicity and systemic properties. Field trials were conducted between 2006 and 2008 in North Carolina and Virginia to test the efficacy of chlorantraniliprole as a drip chemigation treatment on tomatoes. Drip chemigation of chlorantraniliprole at various rates and intervals significantly reduced the percentage of tomatoes damaged by tomato fruitworm (Helicoverpa zea) comparable to that typically achieved from multiple foliar applications of insecticides. The best control was achieved with two applications of chlorantraniliprole at 0.074 kg ai/ha, or a single application at 0.099 kg ai/ha. Residual ingestion bioassays showed that chlorantraniliprole was effectively taken up by the roots and was active in leaves up to 66 days after treatment (DAT), active in blossoms up to 22 DAT, but was not active in fruit. Drip chemigation of chlorantraniliprole may offer several advantages over foliar applications, including ease of application, reduced pesticide input into the environment, reduced worker exposure to pesticides, and reduced risk to beneficial arthropods. Accepted for publication 14 January 2010. Published 7 April 2010.

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