Aphids

Background:

Aphids, generally known as Greenfly and Blackfly are small soft bodied sap sucking insects. They are probably the most commonly known group of plant pests, infesting almost all types of plants, shrubs and trees.

There are many species of aphids and they can be found throughout the world, on every continent. Generally, they feed in colonies and can be recognised by their plump pear-shaped bodies and two tubes (siphunculii), that project from the rear of their abdomens.

Aphids are usually found feeding on the young leaves, new shoots and flower buds where the plant cells are more pliable and high in nitrogen. They push their long piercing mouth parts deep into the plant tissue and suck up the plant sap . Excess sap and sugars are excreted as sticky honeydew which can then promote the growth of sooty moulds and fungi on the infested plants. However, ants are usually attracted to honeydew where they harvest the droplets and therefore reduce sooty mould problems.

Whilst feeding, many aphid species can also acquire and spread plant viruses. Heavy infestations can also weaken plants and cause leaf curling and even plant death. When aphid infestations become large, the colony produces winged adults which then disperse to new plants and establish new colonies.

During the warmer months, the wingless adult female aphids produce 50 to 100 young clones at a rate of up to 5 young per day without having to mate. Young aphids are born live and can start reproducing within just 1 week. Only in the autumn and early winter months will most aphid species produce males. These mate with the females who then produce fertile eggs that over-winter. Because of the extremely fast reproduction rate of aphids during the growing season, it is often difficult to determine the effectiveness of crop protection products. Even when just 5% of aphids survive an insecticide the infestation could return to its original level in a few days.

Using SB Plant Invigorator to control aphids:

Independent research studies have shown that SBPI can be highly effective at controlling aphids if used correctly.

SBPI will produce a significant reduction in aphid numbers if applied thoroughly (to upper and lower leaf surfaces) and to the point it runs off the leaves. However, certain aphid species are more easily controlled than others.

Studies have shown that almost total control of many important aphid species can be achieved with just one or two thorough applications of SBPI, depending on the severity of the infestation. This includes Pea aphids

[Acyrthosiphon pisum](Figs. 1a and 1b), Bean aphid [Aphis fabae] (Figs 2a and 2b), Apple Grain aphid [Rhopalosiphum padi] (Figs. 3a and 3b) and Woolly Apple aphid [Erisoma lanigerum] (Figs. 4a and 4b). However, the extremely fast reproduction rate of any surviving aphids could rapidly restore the infestation to original levels if further applications of SBPI are not made at regular intervals. Weekly applications to susceptible plants are recommended.

The Peach potato aphid [Myzus persicae] (Figs. 5a and 5b), is a more robust aphid than many of the other species and consequently is more difficult to control by physical means. However, SBPI will control established infestations of M. persicae after 2 or 3 applications at 2 or 3 day intervals. Weekly applications can then be used to maintain control.

If necessary, a x2 recommended dose rate of SBPI could also be used for rapid control of M. persicae. However it is advisable to first test delicate plants for phytotoxic response to a higher rate.

SBPI does not affect aphids in the final stage of parasite development (mummies), so it can be used in conjunction with an IPM system using parasitic wasps.

Spraying as often as weekly may seem excessive but please remember SBPI provides foliar nutrients, comprehensive pesticide and mildewcide all at the same time.

Most growers using SBPI weekly rarely use other products. Resistance to SBPI will not occur due to its physical mode of action.