Budworm - Symptoms, damage and how to fight against -

Budworm - Symptoms, damage and how to fight against -


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Budworm or rather budworm

There are several types of budworms that can be found on different varieties of trees, often fruit-bearing but not only. These parasitic caterpillars are called "budworms" because to protect themselves, they wrap the leaves of their host around them, it is there that they form their chrysalis or rather cocoon in the case of moths, where the pupation cycle (the caterpillar turns into a butterfly) will take place between 1 and 2 weeks. The butterfly will not emerge from its cocoon until the conditions are right, that is, depending on the type of budworm, if it is hot and dry, or in the case of other hot and humid types.
Once released, the butterfly will lay many eggs for about 3 weeks.

The grape budworms (or grape worm) that attack you can imagine, in the vineyard, the oriental budworm (Grapholita molesta) which attacks more particularly peach, apple, plum, pear, and apricot. The chestnut moth harms the chestnut. There are still others, which attack oak, hazelnut, conifers, balsam fir and spruce (the spruce budworm which is devastating in Canada and the United States) and many other varieties that are rampant in vegetable gardens, such as the pea budworm. These budworms are the larvae of moths, larger or smaller depending on the type of budworm, from less than 10mm to about 20mm. It is an insect which acts and harms on 2 generations, by attacking first the shoots or the flowers, during this teps occurs the coupling, then the laying, the next generation of larva will then attack the fruits or vegetables.

What damage does the budworm caterpillar cause?

The moth damage, in any case, when the infestation is massive, the harvest can be involved, if not totally, to a large extent. The risk of infestation is longer or shorter depending on the region, the hotter it is, the longer the risk. The butterfly only flies above a certain temperature, usually around 16-18 ° C. The period extends from March to September.
As budworms penetrate fruits and even vegetables, not only do they endanger crops but, for example, in the case of peas, they endanger seeds.

Peach moth, apple tree, peach tree (...):

• A first generation of "caterpillars" attacks terminal young shoots that wither away. In response, the tree produces a kind of gum at the sites of the attack which flows from the bud.
• A second generation will penetrate the fruits and devour their flesh. Often close to the peduncle, a flow of gum appears through the small opening that the larvae create to enter the fruit.

Vine moth:

• On the vine, the first generation of budworm will mainly devour the flowers, thus preventing the fruits from developing. The second generation will enter the fruit. Its color changes first, then the grape rots.

Chestnut moth:

• In the case of chestnuts, the attack is produced directly on the fruits, the chestnuts. We then notice a small hole on the surface of the fruit, as well as residues (excrement of the "caterpillar") hanging from a filament.

Pea moth:

• The butterflies lay small eggs of about 1 mm on the leaves, after hatching, the caterpillars attack the leaves and flowers, then in successive cycles penetrate the pods and peas. The pea budworm is very widely established in a large half of it located to the south of a line that runs from the Bas-Rhin to the Charentes-Maritimes.

How to spot a budworm "attack"?

• Observe crops very early in the season first the foliage and later the fruit.
• Observe the flight of butterflies over the crops in the evening.
• In addition to the signs indicated above, secondly sooty mold can appear on the leaves of infected trees.

Which organic treatment against budworms:

• Bacillus thuringiensis, this is the same treatment used in infestations of moth, woodworm, moth. It is a bacterium that has insecticidal properties, which can be found in small quantities everywhere: soil, water, air and foliage.

Sex pheromone traps are effective: The principle is quite simple, in a trap we deposit pheromones, sex hormones of the female budworm butterfly, the male is attracted, then trapped, he dies without having fertilized the female. Those are effective devices if they are placed in anticipation of attacks, and over time to capture the different generations in areas where infestations are known.
The traps should be in place from the very beginning of spring, the pace may be a little different depending on the type of budworm. But it is generally at the beginning, in the first third of spring that the nymplosis cycle ends with the appearance of the first butterflies in April-May. A few days later they reach their reproductive quality. Male and female subjects mate as soon as temperatures reach around 18 ° C. A few days later (4 to 6 days) the first laying occurs. Each female can lay up to 300 to 400 eggs until late spring. The caterpillars appear in about the first third of summer, in the middle of summer they penetrate the fruits. At the end of summer they leave their host to live in the earth or in the bark of trees where they will start their cycle again.

Illustrative image taken from Wikipedia.org under Creative Commons License 2.0 - Photo by Bernard Dupond.


The pea moth, pest of the pea

Pea budworms colonize plots of protein peas in the spring. They are harmful to the crop when they fly from early flowering. Chemical control is possible, but it must be very precise, as it must target the caterpillars before they enter the pods.


How to recognize scab?

Originally…

Well-known but also feared cryptogamic disease, scab is caused by a fungus, the Ventura inaequalis. And this is thehumidity which is, in the first place, at the origin of its development. If you add a period of high heat, you have the perfect duo to attract scab. Beyond that, any weakened tree is more susceptible to diseases and pests and scab is no exception to the list.

Which trees are affected by scab?

Commonly called apple scab, the disease therefore mainly affects apple trees. Nowadays, it is not uncommon for scab to infest all varieties of apple trees, which seem more fragile than before. But it can also infest other fruit trees such as pear trees and the plum trees. The nature of the fungus changes since the one attacking the pear tree is the Ventura pirina.

When does scab spread on fruit trees?

Scab occurs more at the end of the spring, period of full fruit growth. But the disease can also affect your trees in the middle of autumn if the humidity level is still high.

What are the key symptoms of scab?

This fungal disease causes brown to black lesions on foliage and fruits but also sometimes on twigs and buds. These spots are quite recognizable at a glance by their color and the volume they can occupy.

The damage to fear

  • The leaves eventually close in on themselves and fall
  • Fruits fill with crevices and rot
  • The flowers also fall
  • Photosynthesis is stopped sharply
  • The very development of your trees is in jeopardy.

Which plants are affected by plant viruses?

Sometimes difficult to detect as they cause variable damage from one plant to another, phytoviruses such as plant viruses affect many plants:

  1. Among the flowering plants: gladioli, hydrangeas, dahlias, impatiens or tulips
  2. Among the crops in the vegetable garden: lettuce, potatoes, cucumbers or even tomatoes with "tomato brown rugose fruit virus"
  3. Through trees: pear trees, poplars or even cherry trees… The phytovirus also attacks the vines.

Tomato virus: what is it, what to do in case of suspicion?

ANSES warns against a new virus that threatens tomato, pepper and pepper plants, the first case of which has been confirmed in Finistère. Here's what you need to know about Tomato brown rugose fruit virus (ToBRFV).


IV. Symptoms of root knot nematodes

Symptoms on the root system:

Root knot nematodes are very polyphagous. They attack several host plants (tomato, watermelon, melon, squash, zucchini).

The main visible symptom is the presence of gall on the root system.

In the case of a root attacked by root knot nematodes, we observe the presence of a swelling isodiametral.

When an incision is made at the level of the bulge, using a sharp object (thin blade), a person with a keen eye can potentially see small colored beads within a seemingly normal tissue. white, about the size of half a pinhead (adult females of the parasite).

Symptoms on the aerial parts:

The parasitism of Meloidogyne does not cause specific symptoms to appear on the upper part of the host plant, making the task of detecting them very challenging.

It is rather a general deficiency of the plant following a reduction in the absorption and assimilation capacities of the plant's root system.

The first consequence of this reduction is a reduction in the mineral supply of the plant. The aerial part then presents a puny appearance: growth is retarded, the leaves are reduced and may show symptoms of mineral deficiency. Flowering and fruiting can be greatly reduced.

Photo credit © Scot Nelson - flickr.com - Meloidogyne incognita (Symptoms on the root system of the tomato plant)


How to control the agave weevil?

Do not panic ! The agave weevil, similar to the palm weevil, is only active in a very small part of Europe. It is above all its larva, the agave worm, that should be monitored in risk areas. We tell you everything!

Scyphophorus acupunctatus, adult individual on Agave americana. It quickly hides in the bowels of the plant.

The agave weevil, Scyphophorus acupunctatus, is an insect belonging to the large group of beetles. Its shape is very similar to that of the palm weevil but it is smaller and completely black. Despite its name, it doesn't just attack agaves ...

The agave weevil, a simple cycle

This bug lays on agaves, helped by waist sores carried out in summer (leaves cut between May and September). The larvae develop in the plant, especially in the tenderest tissues of the heart (such as the palm butterfly). At the end of its cycle, which lasts at least a year, the larva gives rise to an adult who has every chance of laying eggs on the plant that gave birth to it, until the latter is exhausted.

Agave americana attacked by the agave weevil. The plant has collapsed but the subject in the background is still savable.

The discreet symptoms of the agave weevil

At first, the damage of the agave worm is not very visible: at most, we notice a few flows at the base of the cone of leaves in formation. At this point, red alert: a healthy agave should not show such signs. When the infestation continues, the tissues succumb and the plant suddenly collapses. It survives by the rejections that form most species (but some do not reject).

The first attacks seem to be confined to one or more large leaves at the base of the plant. Spotted at an early stage, theattack can therefore be contained by cutting the affected tissue, down to healthy tissue. Attacked and infested tissues must be destroyed, by crushing, scalding or deep burial.

Agave weevil damage, cut away. Larvae are visible in light brown areas above. Dark colored tissue is dead and rotting, like gangrene.

Which plants are attacked?

Besides agaves, yuccas (especially Yucca aloifolia and Yucca elephantipes), dragon trees (Dracaena draco), sotols (Dasylirion) and Furcraea (or choca) can harbor this pest. In fact, it is especially Agave americana and the species associated with it (Agave cordillerensis, Agave tecta, Agave ingens, etc.) which are the most exposed.

Where is the agave weevil found?

Currently (in 2019), the area in which agaves are affected by this worm mainly concerns France, and exclusively the Mediterranean rim. It is likely to be seen from Perpignan to Nice, with more marked foci in Perpignan, Béziers, Montpellier and Fréjus. The Dutch authorities recognize that this pest is regularly imported (13 times in the last 30 years).

Outside this area, other European countries are concerned, such as Greece, where our images are taken.

How to cure an agave from the weevil?

Cut off the affected parts until no more affected tissue is found (black). Spray Bordeaux mixture against the risk of bacterial superinfection and sprinkle with charcoal powder to help with healing.

A good source of information for curing an agave from an attack of Scyphophorus acupunctatus can be found in the Fredon Occitanie fact sheets.

5 steps to avoid the agave weevil

  1. Observe a quarantine if you collect them and have them come from various sources. One year of observation is a reasonable time.
  2. Inform neighbors screw. The weevil does not fly more than a kilometer per year. It circulates through infested plants rather than wing pullers.
  3. Avoid cleaning your agaves during the summer months. Cover the cutting wounds with green clay mixed with an insecticide (commercial Spruzit-type mixture).
  4. Inspect your agaves regularly, even outside the infestation area. Do not let the doubt take hold: an agave is easily replaced!
  5. Buy your plants from a reliable supplier who guarantees the quality of the plants they provide to you (this is our case). Refuse any plant that is not accompanied by a phytosanitary passport, mandatory for all plants circulating in Europe from December 14, 2019.

Fun info: called maguey worm, picudo del agave, the agave weevil is the bug that scents mezcal. i Salud i pesetas! (“Health!”)


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