Wheat pests

What pests can weaken a wheat field, reduce plant density, or negatively impact yields even before the damage is fully visible? From sowing to grain filling, wheat can be exposed to several pests: soil insects, aphids, leafhoppers, wheat midges, flies, or slugs, depending on the agronomic context, climatic conditions, and field history. Agrobiotop provides technical support to help you identify the various wheat pests and implement natural solutions tailored to the specific needs of your fields.

Wheat aphids

Wheat aphids comprise several species capable of weakening plants by feeding on sap, and also of transmitting viruses, particularly to young winter cereals. Their impact depends on the species present, the growth stage of the wheat, and the earliness of the infestation.

• Cereal aphid : Rhopalosiphum padi mainly colonizes young winter cereals in the autumn. Its feeding is often secondary, but it is a major vector of BYDV/JNO, causing outbreaks of yellowing, stunting, reduced tillering, and significant losses in early infections.
• Ear aphid : Sitobion avenae infests the upper leaves and then the ears as soon as they emerge. Damage mainly affects heading and grain filling, resulting in a decrease in thousand-grain weight, less well-filled grains, and sometimes a reduction in the number of grains per ear.
• Large cereal aphid : Metopolophium dirhodum develops mainly on leaf blades. It feeds on sap, weakens photosynthesis and is part of the cereal aphid complex, with an increased impact when the crop is already under stress.
• Russian wheat aphid : Diuraphis noxia colonizes young cereals at the base of growing leaves. It causes leaf curling, white to yellow, sometimes reddish, chlorotic streaks, a reduction in the number of leaves and tillers, and then a decrease in yield when the infestation is early.

Leafhopper vector of WDV

The leafhopper vector of WDV is associated with Psammotettix striatus , also known in agricultural contexts as Psammotettix alienus . This hemipteran, belonging to the Cicadellidae family , pierces young plants and can transmit Wheat Dwarf Virus. The most significant damage, therefore, stems not only from nutrient deficiency but also from the transmitted virus: stunted plants, pronounced dwarfism, loss of vigor, and substantial yield losses when infection occurs in the autumn.

Wheat fly

The wheat bulb fly, Delia coarctata , belongs to the order Diptera and the family Anthomyiidae. The larvae penetrate the base of the stems in late winter and then move upwards towards the terminal bud. The main stem yellows, dries out, and detaches easily when pulled. Damage therefore affects both the stems and tillers, resulting in a loss of functional stand that can impair the crop’s ability to form a uniform canopy.

Frit fly

The frit fly, Oscinella frit , is a fly belonging to the Chloropidae family . It attacks wheat seedlings between emergence and the beginning of tillering. The larva consumes the inside of a stem, causing the central leaf to wilt, yellow, and then dry out. The damage is most severe at very young stages, before the plant can compensate through tillering.

Yellow fly

The yellows cereal fly, Opomyza florum , belongs to the order Diptera and the family Opomyzidae . Its larvae destroy the developing ear inside the stalk. In the field, yellowing of the last emerging leaf, a stalk that easily pulls back, and an aborted ear are often observed. Damage frequently affects an isolated stalk, but it can become more noticeable when conditions favor multiple infestations in the same field.

Barley gout fly

The barley gout fly, Chlorops pumilionis , is a fly belonging to the Chloropidae family . The larvae penetrate the shoots and disrupt the development of young stems. Symptoms often include dead hearts, stunted secondary tillers, and less vigorous plants. The risk is particularly high during early sowing and mild autumns, which prolong the periods favorable for egg-laying.

Hessian fly

The Hessian fly, Mayetiola destructor , belongs to the order Diptera and the family Cecidomyiidae . The larvae feed at the base of leaves or at the nodes. Infested plants become stunted, stiff, sometimes bluish-green, with thickened tissues. On young plants, a severe infestation can lead to winter mortality; in spring, it weakens the stems and can hinder heading.

Wheat midges

Wheat midges comprise several dipteran insects of the family Cecidomyiidae , whose damage can affect flowers, developing grains, or stems, depending on the species. Their presence is often linked to sensitive growth stages of wheat, particularly around heading and flowering.

• Orange wheat midge : Sitodiplosis mosellana lays its eggs in the flowers during heading and flowering. The larvae directly consume the developing grain, reducing its size, deforming it, and degrading both yield and technological quality.
• The yellow wheat gall midge , Contarinia tritici, also lays its eggs in the flowers around the heading-flowering stage. The larvae feed mainly on the floral parts, resulting in a reduction in the number of grains through abortion rather than a decrease in the size of the grains already formed.
• Horsetail gall midge : Haplodiplosis marginata migrates under the leaf sheath in its larval stage and feeds on the internodes. It causes saddle-shaped galls, weakens the stems, promotes lodging, and can complicate harvesting during severe infestations.

Cereal leaf beetle

The cereal leaf beetle, Oulema melanopus , belongs to the order Coleoptera and the family Chrysomelidae . The larvae feed on the parenchyma between the veins, often leaving the lower epidermis intact. The leaves then show discolored patches, sometimes very visible in spring. On winter wheat, this damage can appear dramatic, but its impact depends on the level of infestation and the crop’s ability to compensate.

Cereal ground beetle

The cereal ground beetle, Zabrus tenebrioides , is a beetle belonging to the Carabidae family . The larvae live in tunnels in the soil and emerge at night to devour the leaves of seedlings. Sometimes only the veins remain, with leaves pulled into the tunnels and entire seedlings dying off. The losses are mainly manifested by a decrease in plant population at the start of the growing season.

Wireworms

Wireworms of wheat include Agriotes lineatus, Agriotes obscurus , and Agriotes sputator , beetles belonging to the family Elateridae . The larvae live in the soil and attack underground parts of the plant, such as the crown or base of the stems. They bore into, lacerate, or sever the tissues, causing yellowing, drying, stunted growth, and sometimes the death of seedlings. Damage is most severe early in the growing season, when the wheat has not yet established a strong stand.

Wheat beetles

Wheat beetles are hymenopterans of the Cephidae family whose larvae develop inside the stems. Damage is most noticeable at the end of the growing season, when the weakened stems break, fall over, or become difficult to harvest.

• Wheat stem sawflies(Cephus pygmeus) bores into the stem in its larval stage, consumes the pith, and then creates a break zone at the base. The stems may break or fall over before harvest, resulting in losses due to the stems being flattened and poorly recovered.
• Wheat beetle : Cephus cinctus causes a similar damage profile: larvae in the stem, consumption of the pith, weakening of the base, breakage and lodging. It is best known for its impact on North American cereal systems.

Wheat thrips

Wheat thrips are insects of the order Thysanoptera that primarily pierce the ears, floral parts, and ovaries after heading. The damage directly affects grain formation, potentially impacting yield and quality.

• Cereal thrips : Haplothrips tritici pierces floral tissues and ovaries in both the adult and larval stages. Grains can become stunted, deformed, or aborted, with durum wheat being particularly susceptible during flowering.
• Cereal thrips causing floral damage : Limothrips cerealium thysanoptera causes damage to ears and floral parts. Grains develop poorly, quality can decrease, and the damage is highly dependent on the population level at the time of flowering.

Sunn pest

The sunn bug, Eurygaster integriceps , is a hemipteran insect belonging to the Scutelleridae family . Adults and nymphs pierce the leaves, stems, and then the developing grains. The damage affects not only the yield but also the technological quality of the wheat. The feeding punctures on the grain can alter the gluten and reduce baking suitability, making this pest particularly feared in several cereal-growing regions of the Near East, Western Asia, and Southeastern Europe.

Blue oat mite

The blue oat mite, Penthaleus major , belongs to the order Acarida and the family Penthaleidae . It is active in the cool season and pierces leaf cells. The leaves take on a silvery-grey appearance, then the tips turn brown. In heavy infestations, the crop may show stunted growth or even localized dieback, especially when cool conditions prolong the pest’s activity.

Brown wheat mite

The brown wheat mite, Petrobia latens , is a mite belonging to the Tetranychidae family . Its cellular punctures primarily affect the leaves, causing light-colored spots, yellowing, and then a bronze or scorched appearance. Infestations are more damaging when wheat is already under water stress, as the foliar damage further reduces the plant’s ability to maintain photosynthetic activity.

Mite responsible for wheat leafroll

The mite Aceria tosichella , of the order Acarida and the family Eriophyidae , does not have a truly established French name. It colonizes the cornet of young leaves and feeds on the epidermal cells. Damage results in leaf curling, impaired unfurling, and sometimes trapped ears of grain. Its impact can also be exacerbated by its ability to transmit several viruses associated with the wheat streak complex.

Wheat nematodes

Wheat nematodes primarily attack the roots, but some can also deform the above-ground parts or the grains. Their damage often results in irregular patches, slowed growth, reduced tillering, and a decrease in vigor that is difficult to attribute without careful observation. 

• Cereal cyst nematodes : Heterodera avenae, Heterodera filipjevi and Heterodera latipons 
• Root-lesion nematodes : Pratylenchus neglectus and Pratylenchus thornei
• Cereal root-knot nematode : Meloidogyne naasi
• Wheat root knot nematode : Anguina tritici

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