摘要:

AbstractThe photodegradation of the insecticide phosalone has been investigated under UV and simulated solar light conditions. Irradiation of phosalone in solvents such as hexane and methanol yielded a new photoproduct, dechlorophosalone formed as a result of photodechlorination of phosalone. Irradiation in methanol afforded, besides the usual hydrolytic products, three new compounds: phosalone‐oxon; O,O‐diethyl S‐methyl phosphorodithioate; and 6‐chloro‐3‐methoxymethyl‐2‐oxobenzoxazoline. Photolysis of phosalone in the solid state as a thin film on a glass surface produced a number of photoproducts including two new compounds: 6‐chloro‐3‐mercaptomethyl‐2‐oxobenzoxazoline and its dimeric disulfide. Under controlled laboratory conditions, the half lifes of disappearance of phosalone in UV and simulated solar light were found to be 2.5 and 4.75 days on the soil surface and 4.75 and 8.5

ISSN:0031-613X    

DOI:10.1002/ps.2780250102

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAn HPTLC method for determining fluorimetrically the residues of coumaphos in honey samples is described. The active ingredient is solid phase extracted with a C‐18 disposable column and determined densitometrically on HPTLC pre‐coated silica plates. The method does not require additional clean‐up steps, is extremely quick and can easily be adapted to routine determinations of a large number of samples. The determination limit is 0‐01 mg kg−1and recoveries are

ISSN:0031-613X    

DOI:10.1002/ps.2780250103

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA novel range of trimethylstanniomethyl ethers of well known pyrethroid alcohols were synthesised, and their insecticidal activities and modes of action as insecticides were investigated. Among them, ethers from three types of alcohol (3‐phenoxybenzyl, 4‐fluoro‐3‐phenoxybenzyl and 6‐phenoxy‐2‐pyridylmethyl) showed remarkable insecticidal activities against rice stem borers, houseflies and German cockroaches.According to electrophysiological studies on the abdominal nerve cords of German cockroaches, trimethylstanniomethyl 6‐phenoxy‐2‐pyridylmethyl ether induced a rapid decline in spontaneous firing similar to that from tetramethrin. However, insecticidal trimethyltin chloride caused an entirely different response.These observations suggest that the present tin ether derivatives resemble pyrethroids, rather than the insecticidal tin com

ISSN:0031-613X    

DOI:10.1002/ps.2780250104

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe word stability is ubiquitous in colloid science but means different things to different people. In a suspension concentrate it is possible to identify three different physical processes which may lead to instability in a particulate system, namely a change in particle size due to Ostwald ripening, particle aggregation and particle sedimentation. Although these processes may occur simultaneously they are here treated separately in order to promote understanding of the physical forces involved.

ISSN:0031-613X    

DOI:10.1002/ps.2780250105

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effectiveness of two synthetic pyrethroids, cypermethrin and fenvalerate, and of methomyl applied to cabbage plants was tested against the cabbage aphid, Brevicoryne brassicae (L.), and its parasitoid, Diaeretiella rapae (M'Intosh). Dosage rates chosen were equivalent to the manufacturer's maximum and minimum recommendations. Methomyl was considerably more toxic to B. brassicae adults than the two synthetic pyrethroids used. Fenvalerate, at the lowest rate used (71 g ha−1), showed satisfactory effectiveness in reducing aphid adult population on treated plants by c. 77% below that of the control. All insecticides and rates used significantly reduced the emergence of parasitoid adult D. rapae from mummified aphids compared to the control. Fenvalerate clearly had less impact on emergence than cypermethrin or methomyl at any dosage used, while methomyl has appeared to be the most toxic compound in this respect. Longevity of parasitoid adults was highly affected by insecticide application, particularly those adults emerging from mummified aphids exposed to methomyl or cypermethrin. However, only a slight difference in longevity was seen at the lower rate of 71 g ha−1of fenvalerate. At the lowest dosage rates used, methomyl and cypermethrin reduced the F1‐progeny of adult parasitoid females by 70.5% and 58.3%, respectively, of the control, whereas fenvalerate reduced the progeny by only

ISSN:0031-613X    

DOI:10.1002/ps.2780250106

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAdult male German cockroaches were exposed to surface deposits of insecticides for 5 min in the central compartment of a three‐compartment choice chamber illuminated at one end. They were then allowed access to the escape compartments and their distribution recorded over the subsequent 60 min. Cockroaches exposed to pyrethroid insecticides rapidly accumulated in the escape compartment closest to the light source; the same effect was observed to a lesser extent following exposure to propoxur. Boric acid and bendiocarb deposits inhibited the movement of the cockroaches away from the light source, and fenitrothion deposits delayed it. Dieldrin had no effect on the distribution of cockroaches within the choice chamber. The reversal of the normal tendency of German cockroaches to move from a light area to a dark harbourage following exposure to pyrethroids may contribute to the flushing action observed when these chemicals are used for control ofB. germanicapopulation

ISSN:0031-613X    

DOI:10.1002/ps.2780250107

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTwelve 4‐(substituted phenoxy)methyl‐6‐methyl coumarins were synthesised by the condensation of 4‐chloromethyl‐6‐methyl coumarin with various phenols in the presence of potassium carbonate in dry acetone. The compounds were tested for their toxicity towards the mycelial growth of seven plant pathogenic fungi. Among the tested fungi, Pythium aphanidermatum, Colletotrichum falcatum, Drechslera oryzae, Alternaria alternata and Fusarium solani exhibited maximum sensitivity whereas Macrophomina phaseolina and Rhizoctonia solani were least sensitive to the test compounds. The 4‐(4‐tert‐butylphenoxy)methyl and 4‐(4‐nitrophenoxy)methyl analogues possessed greatest toxicity towards the majorit

ISSN:0031-613X    

DOI:10.1002/ps.2780250108

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSpray deposit patterns on simulated and live foliage of balsam fir and white birch were determined at different heights and at periphery and interior locations of the tree crown, following aerial and ground applications of fenitrothion formulations over a boreal forest near Searchmont, Ontario. Droplet size spectra and AI deposits were assessed at ground level with ‘Kromekote’ card/glass plate units. Aerial application was made with a Cessna 188 aircraft fitted with ‘Micronair’ AU3000 atomizers. For ground application, a ‘Soloport’ 423 backpack mistblower fitted with an extension tube and a diffuser nozzle at the tip was used.Deposit data on the ground samplers indicated significantly larger droplets and greater deposits from the aerial spray trial than from the mistblower treatment. However, foliar deposits at tree canopy level were only slightly higher in the former trial than in the latter.Analysis of spray deposits on simulated and live fir foliage showed definite gradients in deposit levels, decreasing from top to bottom crown, and from periphery to inner tree crown. In the birch tree crown, such gradients were not observed. The simulated leaves generally acted as better collectors of spray droplets than the natural leaves. The overall mean deposit values, expressed in ng cm−2, showed a wide variation, although there was generally a close relationship between the deposits on the simulated and nat

ISSN:0031-613X    

DOI:10.1002/ps.2780250109

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper presents an overview of the current status of research on insect neuropeptides. It reviews approaches for identifying insect neuropeptides and their functional roles. It suggests that insect neuropeptide systems can present many potential target sites for the development of novel pesticides.

ISSN:0031-613X    

DOI:10.1002/ps.2780250110

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractDuring trivial flight in locusts, carbohydrates are the main energy source for the flight muscles, but during long‐term (migratory) flight, lipids mobilised from the fat body are utilised. The supply of fuels to the flight muscles, and the balance between fuels, is determined by peptidic adipokinetic hormones, AKH‐I and AKH‐II, released from the corpora cardiaca. These peptides also indirectly effect changes in lipid‐transporting mechanisms in the haemolymph, and regulate a lipoprotein lipase necessary for lipid uptake by the flight muscles. The sequences of the AKHs of locusts are known and they are members of a family of invertebrate neuropeptides. Extensive structure/activity studies for the action of AKHs on lipid mobilisation have been carried out and, together with studies on secondary structure, the structural features necessary for biological activity are being elucidated. Such information will be of great importance in receptor studies for these hormones, and in the development of powerful agonists and anta

ISSN:0031-613X    

DOI:10.1002/ps.2780250111

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY