The selectivity of methabenzthiazuron between barley, perennial ryegrass and Poa trivialis

In field experiments methabenzthiazuron at 1.1 kg ai/ha applied pre-emergence gave good control of Poa trivialis L. in perennial ryegrass S23 which was undersown in spring barley (Zephyr); no significant damage to barley or perennial ryegrass resulted from 2.2 kg ai/ha. However this dose applied when barley had three to four leaves decreased the subsequent barley yield. In pot experiments in the glasshouse methabenzthiazuron was active mainly due to uptake through the soil. Much greater damage to barley and perennial ryegrass resulted when herbicide-treated soil was placed below seed level than above the seed. The difference was less marked with P. trivialis. The latter started to develop secondary roots near the soil surface earlier than either perennial ryegrass or spring barley.     

Structure-activity relationships of 1,2,3-benzothiadiazoles as synergists for carbaryl against the house fly (Musca domestica)

Fifty six 1,2,3-benzothiadiazoles and related compounds were evaluated as carbaryl synergists against the house fly (Musca domestica). Many of these were excellent synergists, the most active being those containing various combinations of halogen, alkyl, or alkoxy substituents in the 5- and/or 6-positions of the ring.Regression analysis on the data from 14 compounds for which substituents constants were available established that synergistic activity can be satisfactorily described by equations in terms of the hydrophobic bonding constant (π) and the homolytic free radical constant (σ ·).The results with compounds related to the 1,2,3-benzothiadiazoles suggest that synergistic activity is associated primarily with the diazosulfide moiety.     

First record of bacillary rickettsia-like organisms in European tick Dermacentor marginatus (Sulzer).

Bacillary rickettsia-like organisms (BRLO) were found in the tick Dermacentor marginatus. They are gram-negative and differ from common bacteria and reckettsiae both in the cultivation conditions and morphology. BRLO are non-pathogenic for ticks and guinea pigs. In our studies they were isolated on half-engorged females of D. marginatus, on which they are still maintained.     

Studies on viremia and antibody formation in ducklings and goslings after experimental infection with Lednice (Yaba 1) virus.

A very low virus level was found for a short time in the blood of ducklings and goslings after experimental Lednice (Yaba 1) virus infection by subcutaneous (scut) and intranasal (inas) route and in blood of ducklings also after infection by intracerebral (icer) route. Subsequently virus neutralizing antibody formation was examined. Antibody formation was found in most of animals. In goslings onset of antibody formation seems to be slower than in ducklings after the same virus infection dose; vice versa, in ducklings antibody titer decreased after 6 weeks. Using low infection virus dose, neutralizing antibody level in ducklings was lower than in the former case. On examining the blood and the organs, the virus was detected in a very low amount and for a very short time in blood and spleen of goslings and only in blood of ducklings.     

Seasonal activity of EPTC for Cyperus rotundus L. control in a tropical climate*

Four experiments were conducted at six week intervals to determine the seasonal activity and persistence of soil-incorporated EPTC (5-ethyl N,N-dipropyl(thiocarbamate)) for Cyperus rotundus L. control and tolerance of okra (Hibiscus esculentus L.), cucumber (Cucumis sativus L.), lettuce (Lactuca sativa L.), red beet (Beta vulgaris L.) and carrot (Daucus carota L.) during the dry and wet seasons in Viçosa, Brazil. Satisfactory control of C. rotundus was obtained at 2 kg/ha EPTC during the dry season and 4 kg/ha or more during the wet season. Only red beet and carrot tolerated these doses of EPTC when the crops were planted five days after application. However, selective control of C. rotundus was obtained when the planting date of lettuce was delayed for three or six weeks after EPTC application. EPTC controlled C. rotundus at half the dose that was required to control three species of annual grass that germinated near the soil surface. EPTC persisted longer when applied to air dry soil and incorporated with a rototiller than when incorporated into moist or wet soil.     

Dissociation and phosphorylation constants for the inhibition of acetylcholinesterase by a series of novel O-ethyl O-phenyl S-n-propyl phosphorothioates

The phosphorylation, dissociation, and bimolecular reaction constants were determined for several members of a series of substituted O-ethyl O-phenyl S-n-propyl phosphorothioates in the presence of substrate. The data obtained are discussed in relation to electronegativity of substituents and in vivo toxicity.     

Field Observations on Blackleg in England1

Inoculation of seed tubers with Erwinia carotnvora (Jones) Bergey et al. var. atroseptica (van Hall) Dye before planting resulted in early death (especially with sprouted seed), blackleg stems and decreased yields. Apical inoculations had most, and stolon inoculations the least, effect on growth and yield. Even plants without blackleg symptoms were more stunted and had fewer stems than plants from uninoculated seed. Rotting of seed tubers often stopped in dry weather and started again later, probably caused, or assisted by, insects breaching the wound barrier. Many other organisms can also rot seed tubers including Phytophthora erythroseptica Pethybridge (pink rot), Fusarium spp. (dry rot), Verticillium spp. (wilts) and Rhizoctonia spp. (black scurf). The bacteria have been shown to spread along rows underground and to different stocks within the same field, presumably in air, but season to season spread by the potato digger has not been demonstrated.     

Chemotaxonomy of Compositae related to their host suitability for Pratylenchus penetrans

Experimental work and a survey of literature gave data on the effects of 175 Compositate on populations ofPratylenchus penetrans in the soil. Nearly 70 Compositae effectively suppress populations ofP. penetrans. It is shown that a close relationship exists between this suppressing feature and the chemotaxonomy of the Compositae.Samenvatting Eigen onderzoek aangevuld met gegevens uit de literatuur gaf informatie over de invloed van 175 Composieten op populaties vanPratylenchus penetrans in de grond. Bijna 70 soorten verlaagden deze dichtheden (Tabel 1). Het betreft soorten van de geslachtenGrindelia, Solidago, Coreopsis, Eclipta, Rudbeckia, Verbesina, Melampodium, Parthenium, Iva, Ambrosia, Milleria, Baeria, Schkuhria, Eriophyllum, Chaenactis, Helenium, Gaillardia, Tagetes, Arctotis, Gazania, Berkheya, Didelta, Echinops enUrospermum. Er is een duidelijk verband tussen de taxonomische indeling van Composieten en deze eigenschap. Bijna alle getoetste soorten van de subtribus Ambrosiinae, Heleniinae, Arctotinae, Gorteriinae en Echinopinae reduceerden populaties vanP. penetrans. In sommige geslachten zoalsSolidago, Coreopsis, Rudbeckia enMelampodium veroorzaakten slechts een of enkele getoetste soorten dit effect.Van de 16 Composieten, waarvan bekend is dat zij -terthienyl in hun wortels bevatten, verlaagden er 15 dichtheden vanPratylenchus. Vrijwel hetzelfde geldt voor Composieten met 5-(3-buteen-1-ynyl)-2,2-bithienyl in hun wortels (Tabel 1). Ook de aanwezigheid in een aantal andere Composieten van een groep rode dithio-acetyleen-verbindingen met waarschijnlijk nematicide eigenschappen in vitro, komt goed overeen met de eigenschap om dichtheden vanP. penetrans in de grond te verminderen.     

The in vivo sensitivity of ATPases to DDT,DDE, and physical immobilization in American cockroaches

American cockroaches injected with sublethal doses of DDT (0.75 μg/roach) at 5-day intervals showed a 40% reduction in oligomycin-sensitive Mg²⁺ATPase from muscle homogenates, and a 23% reduction of Na⁺-K⁺ATPase from nerve cords. Thus, the maximum effect measured occurred with the same enzyme and tissue as determined from in vitro studies. The metabolite, DDE, used at 15 μg per roach, gave no significant change in activity of the ATPase system following injection. In contrast, high single doses of DDT (7.5 μg/roach) and 100 μg DDE and dicofol per roach caused over 30% increase in oligomycin-sensitive Mg²⁺ATPase of muscle and a 10–15% increase in Na⁺-K⁺ATPase of nerve cords measured 24 and 48 hr later. While a similar response was observed for Mg²⁺ATPase activities in cockroaches that were immobilized, the increase in enzyme activities were much greater than that caused by the pesticides.     

Replacement of maize by triticale in broiler diets

1. The nitrogen‐corrected metabolisable energy contents of the triticale varieties Multi Graze, Graze Grain 70, 204 and 131 were 12.28, 12.69, 12.37 and 12.03 MJ/kg respectively.

2. Increasing proportions (0, 25, 50 or 75%) of the maize of a diet were replaced by triticale 131 to provide diets of equal energy and nitrogen contents for broilers. These diets resulted in weight gains of 1.775, 1.782, 1.713 and 1.808 kg respectively at 8 weeks and there were no significant differences among efficiencies of food conversions.

3. Dressed carcass weights as percentages of body weight were 74.38, 75.01, 73.98 and 74.50 respectively and did not differ significantly.

4. Triticale in the diet did not seem to influence the relative weights of either liver or gizzard.

5. The flavour of the meat seemed to become less acceptable as the triticale in the diet increased but there were no significant differences in tenderness and juiciness of the meat caused by the treatments.