The effectiveness of various acaricides against resistant and susceptible carmine spider mites

Two colonies of the carmine spider mite,Tetranychus cinnabarinus (Boisd.), were raised on beans in the laboratory. One originated from roses in a greenhouse which had received acaricidal treatments, and the other fromViola odorata L. in a garden where no pesticides had been used. Laboratory evaluation indicated that the greenhouse strain was highly resistant to dicofol (Kelthane) and bromopro-pylate (Neoron), moderately resistant to propargite (Omite), and slightly resistant to cyhexatin (Plictran); in the garden strain, there was no resistance to any of these acaricides. On a strain of carmine spider mites which was identified and defined as resistant, several acaricides were evaluated in the laboratory for their contact toxicity to the mite by the slide dip method, and for their contact plus stomach toxicity by exposing the mites to sprayed leaves. Some of these acaricides were later tested in the field on two undetermined populations. Cyhexatin, triazophos (Hostathion), fentrifanil (PP-199) and R-28627 killed more than 90% of the mites by both methods and were effective in the field. NC-13292 was an ovicide only. Proclonol (R-8284) had a good effect in the slide dip method but was not so effective in the leaf exposure test. The compounds tested were phytotoxic to rose foliage only, but triazophos burned all the crops tested.     

Radar soundings of the subsurface of Mars

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.     

Interannual and interdecadal variability in 335 years of central England temperatures

Understanding the natural variability of climate is important for predicting its near-term evolution. Models of the oceans' thermohaline and wind-driven circulation show low-frequency oscillations. Long instrumental records can help validate the oscillatory behavior of these models. Singular spectrum analysis applied to the 335-year-long central England temperature (CET) record has identified climate oscillations with interannual (7- to 8-year) and interdecadal (15- and 25-year) periods, probably related to the North Atlantic's wind-driven and thermohaline circulation, respectively. Statistical prediction of oscillatory variability shows CETs decreasing toward the end of this decade and rising again into the middle of the next.     

Productivity of greenhouse roses following changes in soil moisture and soil air regimes

Following 2 years of different soil moisture and air regimes for ‘Baccara’ roses, the optimal regimes were chosen and kept uniform for each growth medium. These regimes were implemented for an additional year (1971–1972).Soil moisture and soil air regimes employed in previous years (1969–1971) had significant after-effects on flower yields in 1971–1972, but no effect on flower quality or weight. The effect of previous suboptimal moisture and air regimes was apparently due to the number of main branches formed per plant in the initial two years, which was unaffected after implementation of optimal regimes.Approximately 4 weeks after cessation of cutting, the root system consituted 11–15% of the total weight of the plant. While 65% of the root system in non-separated beds was located in a soil layer between 30 and 60 cm, only 27% were located above this layer.     

Cotton root and shoot responses to subsurface drip irrigation and partial wetting of the upper soil profile

The ability of cotton roots to grow downwards through a partially-wetted soil (Calcic Haploxeralf) profile toward a water source located beneath them was investigated. Plants were grown in 60-cm-high soil columms (diameter 10 cm), the bottom 15 cm of which was kept wet by frequent drip irrigation, while the upper 45 cm was wetted three times per week up to 20, 40, 60, 80 or 100% of pot capacity. Pot capacity was defined as the water content which gave uniform distribution within the pot and was at a soil matric potential ( _m ) of –0.01 MPa. Plants were harvested 42 and 70 days after emergence (DAE). Root length density was reduced by decreased soil moisture content. At 42 DAE, density was reduced in the soil profile down to 36 cm. The density in the middle segment of the cylinder (24–36 cm) increased at the second harvest, from 0.1 to 0.35 cm · cm^–3 at 40% and from 0.2 to 0.5 cm · cm^–1 at 60% of pot capacity, respectively. A significant rise in root length density was found at all moisture contents above 20% in the two deepest soil segments. It was most marked at 40% where the rise was from 0.2 to 0.8 cm · cm^–3, due to the development of secondary roots at the wetted bottom of the column. When only 20% of pot capacity was maintained in the top 45 cm of the profile, almost no roots reached the wetted soil volume, and root length density was very low. Hydrotropism, namely root growth through dry soil layers toward a wet soil layer was thus not apparent. Root dry weight per unit length decreased with increasing depth in the column at all moisture levels. However, the only significant decrease was, found between the top and the second soil segments and was due to thicker primary roots in the top segment. There was no clear relationship between length and dry weight of roots. Total plant dry weight and transpiration were reduced significantly only at 20% of pot capacity. Dry matter production by roots was less severely inhibited than that by shoots, under decreased moisture content in the soil profile. Leaf water potential decreased when the soil moisture content of the top 45 cm of the profile was reduced below 60% of pot capacity. It was concluded that even at soil moisture content equivalent to a _m of 0.1 MPa, the rate of root growth was sufficient to reach a wetted soil layer at the bottom of the soil column, where the plant roots then proliferated. This implies that as long as the soil above the subsurface dripper is not very dry there is no real need for early surface irrigation.     

Behaviour of phosphamidon within the young almond fruit,and action of translocated phosphamidon and monocrotophos on the egg and the young larva of the almond wasp,Eurytoma amygdali

The use of systemic insecticides to control the egg or the young larva of the almond wasp, Eurytoma amygdali, within the nucellus of the young almond fruit was examined. Phosphamidon was found to leave low, but very persistent residues in the seed, and rather high and persistent residues in the pericarp of the fruit. Phosphamidon and monocrotophos were applied as sprays at three different phenological dates. They did not prevent hatching. 0.03% Phosphamidon was effective in killing the larvae when applied after about 66% had hatched, but had little or no effect when applied earlier, when only 12% of the eggs had hatched, or later, 2 weeks after termination of hatch. 0.06% Phosphamidon was effective when applied at 12% hatch, but not when applied 2 weeks after the termination of hatch. 0.08% Monocrotophos was particularly effective at both application times.     

Massive CO₂ ice deposits sequestered in the south polar layered deposits of Mars

Shallow Radar soundings from the Mars Reconnaissance Orbiter reveal a buried deposit of carbon dioxide (CO(2)) ice within the south polar layered deposits of Mars with a volume of 9500 to 12,500 cubic kilometers, about 30 times that previously estimated for the south pole residual cap. The deposit occurs within a stratigraphic unit that is uniquely marked by collapse features and other evidence of interior CO(2) volatile release. If released into the atmosphere at times of high obliquity, the CO(2) reservoir would increase the atmospheric mass by up to 80%, leading to more frequent and intense dust storms and to more regions where liquid water could persist without boiling.     

Effects of steroid hormone treatment on mammary development in prepubertal heifers

The objective of this study was to determine the effects of steroid hormone implantation in heifer calves on the ability of mammary tissue to develop subsequently in organ culture. Twenty-four calves were paired by date of birth and assigned to groups (eight calves/group). At 4, 7, or 10 mo of age, calves were implanted subcutaneously (s.c.) with pellets containing cholesterol or cholesterol, 17β-estradiol, and progesterone for 9 or 18 d. The calves were euthanized and uteri and mammary glands were removed and weighed. Slices of mammary parenchymal tissue were incubated for 5 d at 37°C in a 50% O₂, 5% CO₂ humidified atmosphere in Waymouth’s 752/liter medium supplemented with insulin (5.0 μg/ml) or lactogenic hormone complex insulin (5.0 μg/ml), aldosterone (0.1 μg/ml), hydrocortisone (0.1 μg/ml), and prolactin (1.0 μg/ml) in the presence or absence of epidermal growth factor (EGF) (0.06 μg/ml) to promote lobulo-alveolar development. Tissue sections were stained and mounted on slides for morphologic and histologic analysis or prepared to evaluate expression of β-casein mRNA. There were no morphologic differences in slices from calf mammary tissues despite age, steroid hormone priming, or hormones used in tissue culture. The 4-mo-old calves required steroid priming followed by incubation of the tissue slices with the lactogenic complex with or without epidermal growth factor to induce cytological changes associated with lactogenesis but did not express β-casein mRNA. At 7 mo of age, steroid hormone priming was not necessary for induction of alveolar formation and secretion. Incubation of the tissue slices from 7-mo-old calves with the lactogenic complex was sufficient to induce alveolar formation and secretion. However, β-casein mRNA was not expressed. At 10 mo of age, exposure of tissue from calves to the lactogenic hormones caused histologic changes reminiscent of the ability to secrete milk regardless of hormone priming. However, estrogen and progesterone priming was necessary before incubation of the tissue slices with the lactogenic hormones to induce β-casein mRNA expression. When epidermal growth factor was added to the lactogenic hormone complex, β-casein mRNA expression decreased. These data support the concept that there is a sequential development of responsiveness of the mammary gland to various hormones. By 10 mo of age, prepubertal heifers reach a stage of maturity where steroid hormone priming followed by incubation of tissue slices with the lactogenic hormones is sufficient to induce both structural and functional differentiation.