Aphids activity

The simple amide, N-methyl amide, and N,N-dimethyl amide substituents maintain aphid activity but now we see good to excellent activity against bean beetles. A ile mexican bean beetles are the most sensitive of the non-aphid insects tested, good activity was seen in several species. The table shows that larger amide substituents as well as the longer spacers maintain activity. 

Imidocloprid [105827-78-9] l-[(6-chloro-3-pytidinyl)methyl]-N-nitro-2-imida2ohdininiine (4) (bp 137—144°C, vp 0.2 )J.Pa at 20°C) is soluble to 0.51 g/L. It is a synthetic nicotinoid with both contact and systematic activity against aphids, leafhoppers, whiteflies, and other sucking insects. The rat LD qS are 424 male, 475 female (oral), and 5000 (dermal) mg/kg. 

There are marked species differences in A-esterase activity. Birds have very low, often undetectable, levels of activity in plasma toward paraoxon, diazoxon, pirimi-phos-methyl oxon, and chlorpyrifos oxon (Brealey et al. 1980, Mackness et al. 1987, Walker et al. 1991 Figure 2.10). Mammals have much higher plasma A-esterase activities to all of these substrates. The toxicological implications of this are discussed in Chapter 10. Some species of insects have no measurable A-esterase activity, even in strains that have resistance to OPs (Mackness et al. 1982, Walker 1994). These include the peach potato aphid (Myzus persicae Devonshire 1991) and the... 

Field beans grow well on clay soils and heavy loams, provided they are well-drained and limed (pH above 6). Winter beans are not frost hardy and so are risky to grow, north of the Midlands. In some rotations, beans replace the clover break and they are usually followed by wheat. Yields for spring and winter field beans are shown in Table 5.4. The problem with field beans is their variable yield, which is partly caused by adverse weather conditions and susceptibility to pests and diseases (winter beans get chocolate spot, spring beans are aphid prone), and partly due to the uncertain activity of the necessary insect crosspollinators. 

As tree fruit species are perennial crops, year-to-year influences are often detected. For example, factors in the previous year(s) (e.g. water or nutrient deficiency, hail storm damage, shoot deformation caused by aphids, too high or too low crop load) strongly influence the tree s performance in the next year (Tromp and Wertheim, 2005). Thus, a major objective of agronomic practices used is to buffer the orchard from stress and to keep trees in a balance/equilibrium between vegetative and generative activity. 

It can also be made by nitrating diethyl phenyl phosphate below 0°. It is a red oil, almost insoluble in water, and Schrader found it effective against aphids, while Ball and Allen1 proved it active against the housefly, milkweed bug and cockroach. Later work showed it active against the two-spotted spider mite. 

Tjalllngil, W. F. "Stylet Penetration Activities by Aphids" Dissertation, Agricultural University, Wagenlngen, The Netherlands. 1985, 100 pp. 

Finally, density-dependent mortality from various enemies may be enhanced by host plant variation. Again, focusing feeding activities on a restricted set of suitable tissues should also focus the activities and abundance of pathogens, parasitoids, and predators. Sessile insects, such as gall-forming aphids (55,62),... 

In addition to being an active ingredient in tobacco smoke and having a pharmacological effect on humans, nicotine (in solution) is effective against aphids, thrips, and leaf hoppers and can he used as a fumigant. 

The tobacco compound nicotine has been used as an insecticide for over 200 years. It is especially effective against sucking insects, such as aphids, and has excellent contact activity. Related compounds are neonicotinoids (e.g., imidacloprid), which have similar insecticidal activity, but are less toxic to mammals. Nicotine and imidacloprid mimic the action of acetylcholine, which is the major excitatory neurotransmitter in an insect s central nervous system. The action of acetylcholine is stopped by the enzyme acetylcholinesterase, which rapidly breaks down acetylcholine. Nicotine and imidacloprid are also neuroexcitatory, but do so persistendy, since they are not affected by acetylcholinesterase. Overstimulation of the nervous system often leads to convulsions, paralysis, and death. 

---