Winter aphids

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. 

A pair of meadowlarks, for example, may feed their nestlings up to 10,000 grasshoppers, plus many other kinds of bugs. Aphids and codling moth pupae are favorite winter foods for several bird species. Clusters of aphids left on strong, established plants that can tolerate them will make a "nursery" for parasitic wasps and predators to feed and breed on. So give nature a chance before you take action against a pest attack you may find that the job has been done for you. 

Apple problems Aphids like to colonize tender shoot tips if they go unnoticed, it may become neoessary to prune out badly infested and distorted growth near right). A proteotive band far right) used to prevent wingless female winter moths from olimbing trees to lay their eggs, may also help with aphid problems—by keeping ants, which farm aphids, out of the tree. 

Susceptible plants Most plants may be attacked by aphids. Many aphid species are plant-specific, such as the lupine aphid, while others, such as the peach potato aphid, will attack hundreds of different types of plants. Aphids may spend the summer on certain plants, moving to a different host species for the winter. 

The earwig can be a pest in some situations, but it is also a useful predator, particularly of apple pests such as codling moth and aphids. Earwigs lay eggs in the soil in late winter, which hatch in early spring. There may be a second generation. 

Small, yellow-white, wingless, waxy pests with dark spots on the abdomen, found among lettuce roots during summer. Overwinters mainly on Lombardy poplar, moving in June to lettuce and sow-thistle. Root colonies can persist into winter, and may survive in the soil until the next season. See a/so Aphids. 

Deltamethrin is a crystalline powder, white or slightly beige in color. The formulations include emulsifiable concentrates, wettable powders, ultra-low volume and flowable formulations, and granules. There are no known incompatibilities with other common insecticides and fungicides. It is used as a contact poison to control apple and pear suckers, plum fruit moths, caterpillars on brassicas, pea moths, aphids (apples, plums, hops), winter moths (apples and plums), and codling and tortrix moths (apples). It also is used in control of aphids, mealybugs, scale insects, and whiteflies on glasshouse cucumbers, tomatoes, peppers, potted plants, and ornamentals.9-11... 

It is of particular importance to watch out for any signs of scab and mildew, as well as aphids, red spider mite and rust mite. Young splice or bnd grafts which are starting to sprout can be damaged by the grapevine weevil [Rhynchites conicus]. In some areas of Europe it is absolutely essential to check the nursery for voles before winter dormancy (catch them with traps or fumigate the burrows). 

A reduction in winter egg laying by rosy apple aphids can be observed in orchards which lose their leaves quickly because of early termination of shoot growth in autumn. 

The apple grass aphid hatches from the winter eggs as soon as the huds open. The nymphs suck on the rosette leaves or flower buds. At the beginning to middle of May they migrate to weeds (preferring annual meadow grass). The infestation then decreases abruptly. In autumn they return to the apple tree, where they copulate and the females lay the winter eggs on the old wood. 

In Europe, fertile sexual forms cannot develop in the autumn. The semi-adult aphids migrate down again to the winter retreat. 

Areas of application Mode of action How obtained Remarks Aphids, blossom weevils and other weevils, tortricids, winter moth, bugs, noctuid moths Contact, ingestion and inhalation insecticide Pyrethrum is produced from chrysanthemums and contains piperonyl butoxide as an additive which increases UV stability Very broad spectrum of action Not completely harmless to beneficials Pyrethrum is poisonous to fish Sprays consisting of pyrethrum alone are also commercially available (e.g. Spruzit)... 

For heavy infestations, knock aphids off with a strong spray of water. Or try insecticidal soap spray, which kills aphids on contact. Pyrethrin also kills aphids, but reserve this as a last resort since it also kills beneficial insects. Apply dormant oil spray in the winter to suffocate aphid eggs. 

If young leaves are yellow, deformed, and stunted, the plant has curly top virus. Deformed leaves may die. If older leaves are also mottled, the plant is suffering from mosaic virus, also called blight or yellows. Destroy infected plants. Control aphids, which spread mosaic as they feed, and beet leafhoppers, which transmit curly top. Prevent some problems by planting mosaic-tolerant cultivars such as Indian Summer , Melody , and Winter Bloomsdale. 

Uses Control of over wintering of aphids, psyllids, ermine moths, winter moths, scale insects and spider mites on prone fruit, control on insects in vines, annual broadleaved weeds in cereals, maize, legumes, etc. 

Allelochemicals are most notable in examples of host-plant and nonhost-plant selection, a process that is vital for phytophagous pest insects to locate food plants and avoid unsuitable or toxic hosts. Aphids have taxonomi-cally unrelated summer and winter hosts. The bird-cherry-oat aphid, Rhopalosiphum yadi. is able to detect species-specific odors from each of its hosts, the bird-cherry tree. Prunus padus, in winter and summer cereal crops. One such allelochemical from the winter host is methyl... 

Those aphids which survive the summer on the hop produce winged forms, both male and female, in early September which migrate back to the damson. Here wingless females are born which lay the eggs that survive the winter. It is obviously desirable to eliminate Prunus spp., which can act as host to aphids and the prunus necrotic ringspot virus, from the vicinity of the hop garden. 

If 50% of winter cereal plants have eggs present then consider a foUar insecticide treatment. Threshold for grain aphids at flowering is when two thirds of the ears are infected. Do not treat if more than 5% of aphids are mummified. Threshold for leaf aphids is when 50% stems are infected. 

Aphids over winter as adults or as eggs on brassica host Eggs hatch in spring and aphid move to underside of leaves and shoots. Winged forms migrate from end of May to infest other crops. 

Not all brassicas affected. Several weeds are hosts to this aphid. Populations vary widely each year due to weather conditions. Threshold for treating winter oilseed rape is 13% plants infected before petal fall. 

Time of sowing can be very important for reducing pest problerrrs. Cereal growers in high-risk areas normally drill winter cereals after the rrtiddle of October to reduce aphid attack arrd trarrsfer of barley yellow dwarf virus (BYDV). MairKrop carrots are sown at the end of May or in early Jrme to avoid the first generation of carrot fly. 

The main pest problem which requires control, particularly in early-drilled winter barley, is to reduce barley yellow dwaifvirus transmitted by aphids (Table 7.1). In very susceptible areas the seed should be treated with clothianidin or an aphicide shorrld be applied at the end of October to the emerged crop. Early-drilled crops may reqrrire two apphcatiorts. 

Slugs may be a serious problem of winter oilseed rape, particularly in trashy or cloddy seedbeds or when late established. Metaldehyde or equivalent should be applied where there is a high risk, and method of establishment may influence the timing of this application. The peach-potato aphid may need a pyrethroid or pirimicarb spray in October/November, but populations of the aphid are highly resistant to both. 

Vims spread by peach potato aphid. Mild winters favour survival of aphid and disease spread. TuYV is a persistent vims. 

---