Non-potato aphids

These aphids are found in the country on plantations of various cultivated plants and weeds. They belong to the most important aphids in the agricultural environment and among non-potato aphids. They overwinter in various forms on their host plants, winter hosts, or in heated greenhouses. The species are sometimes caught in large numbers in yellow traps in spring. They are polyphagous and also feed on many plant species as secondary hosts. In Europe, their occurrence has intensified in recent years, mainly due to climate warming. In Europe, they develop mainly holocyclically, and sometimes only anholocyclically.

Occurrence and harmfulness

The species occur very abundantly in Poland, mainly during warm springs and in areas where their winter hosts or intermediate hosts are present – peas, potatoes, cereals, vegetables, trees, and weeds.

Aphids reach potatoes mainly as a result of secondary dispersal flights. They cannot develop on potatoes and arrive there only accidentally. They may be vectors of many viruses (Table 1), including PVY, which is currently the most economically important potato virus in our country. Their ability to transmit PVY strains is, however, significantly weaker than that of aphids that are host-associated with potatoes (Table 2). The pressure of these aphids in Poland is variable; studies by many authors also indicate transmission of PVM and PVY by Acyrthosiphon pisum and Rhopalosiphon padi (the latter also transmits PVS). Due to the large acreage of cereals and maize in Poland, cereal aphids may therefore be of great importance. These aphids constitute an important group of non-potato aphids. Their significance changes from year to year depending on weather conditions. In dry years with warm spring periods, they occur in much higher numbers than in cold and wet periods.

Economic threshold

Not established for potato.

To monitor aphid occurrence, frequent field observations after planting and during the summer growing season are sufficient. For mechanical trapping of aphids from the environment, a Johnson aspirator can be used. Monitoring can be conducted using yellow traps (winged aphids) or by counting aphids on the underside of leaves from the middle tier of plants (100-leaf method).

Due to their early appearance, they may pose a significant threat to young potato plants that have not yet developed age-related resistance.

Control methods

Not developed for species not host-associated with potato.

The basic method of crop protection is treating seed tubers with an insecticidal dressing in spring (during planting). Currently, only one such treatment is available – Prestige Forte 370 FS, containing an active substance with systemic action. However, the most common measures are foliar applications of insecticides (aphicides). The first treatment should be carried out when the first individuals are detected on leaves or in yellow traps. Subsequent treatments should be performed at intervals of no more than 7–14 days, taking into account the actual threat.

Spraying plantations with mineral oils does not usually control aphids, but it can reduce their abundance and hinder potential feeding on potato leaves. Nevertheless, mineral oil significantly limits virus transmission, hence its important role in potato seed production.

It is also very important to avoid weed infestation of plantations, due to the possibility of viruses surviving in weeds, and because weeds themselves (e.g. Chenopodium album – common lambsquarters) are hosts for some aphids, such as the black bean aphid (Aphis fabae). Excessively one-sided nitrogen fertilization (above 150 kg/ha) leads to excessive plant growth and creates better conditions for aphid development.

Essential oils of some plants are also important in limiting aphids – acting as repellents or control agents. There are many studies in the literature demonstrating satisfactory effectiveness of oils from rosemary, lavender, thyme, and peppermint. However, their application methods still pose many technical problems.

Other methods to reduce aphid landings on plantations include covering ridges with shredded cereal straw or using trap crops sown in strips around plantations (soybean, sorghum, wheat, oats). Both methods, by reducing the number of potential vectors, significantly decrease PVY infection of tubers.