Tomato Pests and Diseases: Complete Guide with photos and tips

Last updated on October 23rd, 2023 at 08:19 pm

In today’s article we will talk about tomato pests and diseases. We are going to start with a series of articles summarizing the diseases and pests that can affect the different crops in the garden and then we will talk about each of them and how to treat them. Let’s start with tomatoes!

Tomato Pests and Diseases: Complete Guide with photos and tips

Tomato Pests

Tomato Pests and Diseases: Complete Guide with photos and tips


Tomato Tuta absoluta

Tuta (Tuta absoluta): The symptoms caused by this lepidopteran are wide mines that leave the epidermis intact but traces of excrement can be seen inside. The shoots become moth-eaten and the tomatoes show holes and blackened internal areas.

Tomato Pests and Diseases: Complete Guide with photos and tips
Tuta absoluta on leaf

Tomato caterpillars

Tomato hornworm (Heliotis sp.) and other caterpillars (Helicoverpa spp., Spodoptera spp., Autographa gamma, etc.): We find some perforations of considerable size through which, sometimes, we can see the caterpillar eating our fruit. We can also observe gnawing on leaves, flowers, fruits and tender shoots, usually with excrements and WITHOUT SLUGS (it gives us the clue that it is not a snail or slug).

Aphids on tomato leaves

Aphids (Myzus persicae, Macrosiphum euphorbiae, Aulacorthum solani…): Aphids produce a rolling and crinkling of leaves downwards. In addition, you can see colonies of these small dark or greenish colored insects, especially on the tender shoots of the developing plant. Another clue is the presence of honeydew (a sugary, sticky substance) and ants around them defending them.

Tomato Pests and Diseases: Complete Guide with photos and tips
Winged aphid with its offspring

Whitefly on tomato

Whitefly (Trialeurodes vaporarium, Bermisia tabaci): We can see small white flies (which are not really flies) with a characteristic erratic flight when shaking the plant. In addition, like aphids, they release honeydew. They are usually arranged on the underside of the leaves.

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Tomato Pests and Diseases: Complete Guide with photos and tips
Macrolophus pygmaeus, one of the insects used for biological control of whiteflies.

Spider mite on tomato

Spider mite (Tetranychus urticae): Spider mite is a mite that leaves discolored leaves with small spots and silks. If it affects significantly, it can cause desiccation and defoliation of the plant.

Tomato Pests and Diseases: Complete Guide with photos and tips
Symptoms red spider mite on leaf

White spider mite on tomato

White spider mite (Polyphagotarsonemus latus): This mite leaves leaves bulging, curved, darker and with elongated appearance and protruding nerves.

Tomato Pests and Diseases: Complete Guide with photos and tips
White spider on a crop

Tomato vasates

Vasates (Aculops lycopersici): the leaves of the tomato plant dry out and take on a pinkish coloration and the stem turns tan until both dry with a reddish-yellow color due to this mite.


Liriomyza or tomato leafminer fly

Leafminer fly (Liriomiza spp.): It makes clear and sinuous galleries in the leaves.

Tomato Pests and Diseases: Complete Guide with photos and tips
Here we see what liriomyza trifolii looks like as an adult

Tomato flower thrips

Flower thrips (Frankliniella occidentalis): Damaged plants show leaves with small, irregular, silvery spots, corresponding to lesions on the underside.

Tomato Pests and Diseases: Complete Guide with photos and tips
Trips, very small black insects

Diseases in Tomato

Downy mildew (Phytophtora infestans): Initially, the leaves of the plant show yellowish spots with an oily appearance that turn brown, necrotizing the center.

On the underside there is a thin white veil that corresponds to the spores. On the stem, we find elongated brown spots that symbolize necrosis and wilting of the plant. The crop takes on a burnt appearance. On the developing fruits, soft brownish spots are observed, generally on the upper half of the fruit.

Tomato Pests and Diseases: Complete Guide with photos and tips
Downy mildew on tomato

Tomato powdery mildew

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Oidiopsis (Leveillula taurica, Phytophtora capsici, Alternaria solana): We find yellowish spots on the upper side of the leaf that quickly necrotize and a kind of whitish powdery mildew appears on the underside.

Tomato Pests and Diseases: Complete Guide with photos and tips
Oidiopsis. Fungi on tomato leaves

Tomato Alternariosis

Alternariosis (Alternaria solana): On lower leaves there are circular brown spots in concentric rings. On stems and petioles, the spots are black and very well delimited. In fruits, there is a depressed necrosis covered with a black mold.

Tomato Pests and Diseases: Complete Guide with photos and tips
Alternaria on broccoli

Root and stem rot of tomatoes

Neck and root rot (Phytophtora spp. Pythium sp., Rhizoctonia solani, Sclerotinia sp. etc.): Young plants wilt presenting strangles and rots in the collar (the lowest area of the stem bordering the substrate).
Vascular worm infestation 

Vascular Fusarium (Fusarium oxysporum sp. lycopersici): wilting and flaccidity of the upper leaves, marked during hot weather. Progressive yellowing and necrosis of leaves from bottom to top, with green nerves.


Bacterial black spot

Bacterial black spot (Pseudomonas syringae pv. tomato): In all aerial organs of small tomato plants we found black spots of irregular contour. On leaves, the spots have a yellow halo and can dry them out. On tomatoes, small black pustules are found, often with a lighter “eye” in the center.

Tomato Pests and Diseases: Complete Guide with photos and tips

Nematodes

Nematodes (Meloidogyne spp.): Nematode-infected plants show weak growth, wilting, chlorosis and roots with deformations and galls (nodules). Distribution in stands (plants forming more or less circular areas) or following irrigation lines.

Tomato Pests and Diseases: Complete Guide with photos and tips
Melodoigyne sp nodules on Lettuce

Tomato virus

Viruses: leaf mosaics, dwarfism, chlorotic (yellow) rings, curling and curling of leaves, fruit deformations with wavy spots or rings…

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Tomato Pests and Diseases: Complete Guide with photos and tips
Tomato spoon virus

Common Tomato and Pepper Pathologies

Physiopathologies are diseases caused by abiotic factors, i.e., there is no causal pathogen but rather poor environmental conditions such as nutrient deficiencies or excesses, low or high temperatures, drought or poor irrigation management or salinity, among others.


Tomato rotting asses

Necrosis or apical rot of fruits (“rotten butts”): A depressed black spot, usually round, appears at the base of the tomato.

Tomato Pests and Diseases: Complete Guide with photos and tips
Rotten butts in tomato can occur both early and late

Tomato scorch or scorching

Fruit scorch: On the side of the fruit exposed to the sun, a depressed white area appears leaving the tissue with a papery appearance and, if the fruit is still young, a scar is formed.

Tomato Pests and Diseases: Complete Guide with photos and tips
Tomato blight

Cracking of tomatoes

Fruit cracking: Appearance of longitudinal or concentric cracks around the peduncle area of the fruit that can take on the appearance of cork.


Tomato leaf curl

Leaf curling: Tomato plants curl upwards the leaflets of their leaves, giving the plant a curled appearance.

Author

  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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