Lobesia botrana

Lobesia botrana

The European grapevine moth or European grape worm (Lobesia botrana (Denis & Schiffermüller, 1775)), is a moth belonging to the Tortricidae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Animalia,
Subkingdom Eumetazoa,
Superphylum Protostomia,
Phylum Arthropoda,
Subphylum Tracheata,
Superclass Hexapoda,
Class Insecta,
Subclass Pterygota,
Endopterygota cohort,
Superorder Oligoneoptera,
panorpoid section,
Order Lepidoptera,
Glossata suborder,
Infraorder Heteroneura,
Ditrysia division,
Superfamily Tortricoidea,
Family Tortricidae,
Subfamily Olethreutinae,
Lobesiini tribe,
Genus Lobesia,
Species L. botrana.
The terms are synonyms:
– Eudemis botrana (Denis & Schiffermüller, 1775);
– Lobesia botrana Jacquin, 1789;
– Lobesia vitisana Jacquin, 1788;
– Olindia rosmarinana Millière, 1866;
– Polychrosis botrana (Denis & Schiffermüller, 1775);
– Polychrosis flavosquamella Dufrane, 1960;
– Tortrix botrana (Denis & Schiffermüller) 1775.

Geographic Distribution and Habitat –
Lobesia botrana is a polyphagous species, which creates particular and, in some cases, significant damage to vineyards and which lives on vines, and other marginal spontaneous plants to vineyards. In fact, it has also been reported on species of the genera Clematis, Crataegus, Ligustrum, Mirthus, Rhamnus, Ribes, Viburnum, Ziziphus, as well as on olive and kiwi.
The most economically relevant infestations occur on the vine and where it can carry out its entire cycle.
Lobesia botrana was first reported in the late 19th century. Although it prefers hot-dry environments, it is also often present in northern Italy where it coexists with Eupoecillia ambiguella.
In Italy it is however widespread throughout the peninsula, reaching as far as the Mediterranean countries.

Morphology –
Lobesia botrana is a moth which in the adult stage is a butterfly with a wingspan of 10 – 15 mm, gray in color with yellow-brownish and blue variegations that draw an intensely marbled livery.
The egg of this butterfly has a diameter between 0.6 and 0.7 mm; it is lenticular, flattened, sub-round in shape. It is yellowish when spawned and then later becomes light gray and then darkens on one side in the “black head” stage and blackens near hatching.
The eggs are laid on the flower buds in the first generation, on the berries in the following ones. A female can lay up to a hundred eggs.
The newborn larvae have a whitish or light hazelnut color; the head is brownish in colour, while the mature larvae, which measure about 9-10 mm in length, (V stage) generally take on a yellow-greenish colour, even if with high variability within the species. the chrysalis or pupae are brown – reddish; these are wrapped in a whitish silky cocoon. The dimensions, usually greater in the females, vary from 4 to 6 mm.

Attitude and biological cycle –
Lobesia botrana is a moth which, as a rule, completes 3 generations per year but in some regions, such as in Italy (Puglia, Lazio, Sardinia) or in Greece and Portugal it is possible to observe a 4th generation. Exceptionally, in particular years, there have been 4 generations also in Northern Italy.
The butterfly overwinters as a chrysalis protected by a silky cocoon hidden under the rhytidoma of the vine or other host plants.
The first flickering occurs starting from the second half of April and throughout the month of May, when the first flight of the adults endowed with prevalent twilight activity can be noted.
After 3 to 4 days, the fertilized females lay eggs on the flower buds or on other parts of the inflorescence. Each female can lay 40 to 100 eggs.
After 7 – 10 days the larvae emerge, which hatch from the egg and penetrate inside the flower buds, feeding on them and wrapping them with silky threads forming glomeruli. The first larval generation is called anthophagous.
After about 20 – 30 days the larvae incrisalidate for 10 – 15 days under the barks or in the glomeruli created by themselves and towards mid-June – early July there is the emergence of the adults of the 2nd flight which ovide on the well-formed berries, giving origin to the 2nd generation larvae (the so-called carpophagous larvae). This generation lives off the grapes, where the adults lay eggs. After an incubation of 4 – 5 days the larvae begin their trophic activity by feeding on the grapes, penetrating the berry on one side and exiting on the other to enter the next berry.
Normally there is also a third generation with the adults appearing in the second half of August and in September with the possibility of a further generation in southern Italy and in favorable climatic conditions.
Subsequently, the larvae of the third or fourth generation, after having exercised trophic activity on the ripening berries, pupate in a crevice of the bark where they spend the winter wrapped in a silky cocoon.
The biology of this moth is linked to climatic conditions. The adults have a mainly crepuscular activity, favored by temperatures above 15 °C with an optimum around 25 °C, while 9 °C are sufficient for the embryonic development. it has been noted that females have an increase in flight activity and oviposition with relative humidity values between 40 and 70%; below 40% the percentage of hatched eggs decreases considerably.
In conditions of high presence of Lobesia botrana, considerable damage can be caused by the larval stage. The larvae of the first generation attack the flower clusters (anthophagous generation), feed on the single flower buds also building silky nests; these are visible in the inner part of the bunch; this generation is not very harmful both because the damage to the single flowers is bearable (for some tight bunch varieties it could even be a good thing), and because the attack is usually never massive.
The larvae of the second generation represent a much greater danger threshold, as they feed on the berries (carpophagous generation), entering and emptying them.
The attack is evident as the grapes wither and darken; on closer inspection, one can see the entrance or exit holes and possibly also the larvae which take shelter in whitish silky shelters, more or less lax, built inside the bunch. In some northern regions there are only 2 generations but, as mentioned, in most cases this moth also completes a third and, sometimes, a fourth generation; these larvae behave like the previous one, attacking the berries.
In these cases these generations occur at the end of summer, when the berries are in the ripening phase, and are even more dangerous due to the complications of a fungal nature (Botrytis and acid rot) which can develop on the wounds caused by the larvae.

Ecological Role –
Lobesia botrana is a moth known for the serious damage it causes by feeding on grape berries and, together with Eupoecilia ambiguella, constitutes one of the main entomological adversities of the vine.
Up until now, the fight against this butterfly has been carried out with guided fight techniques which were based on monitoring performed either with sampling techniques or with the use of sex traps. It is also possible to follow the indications of the provincial or zonal integrated pest management bulletins.
Unfortunately the cultivation specialization of the vineyards, especially in large areas, the decrease in biodiversity, even within the vines, of entire areas, the lack of refuge places for natural antagonists, linked to intensive agricultural practices (fertilization, processing, use of ) has greatly aggravated the relationship between this pest and the vine.
The first technique to compensate for this imbalance is that of introducing agroecological rules and principles, many of which must be thought of even before the vineyard is planted.
Currently, Lobesia botrana is the most dangerous pest for Italian viticulture.
In vineyards, and even better districts, cultivated with vines, the principles of organic agriculture and even more of agroecology can lend themselves to a much more effective control of this moth.
In this sense, some agronomic practices and beneficial insects can play a very important role. Spiders (arachnids), earwigs (dermaptera), chrysopid neuroptera, hoverflies and tachinids, hymenoptera, and other insects that are good predators of moth larvae and eggs.
But these organisms need, in order to live and therefore become antagonists, an adequate ecosystem. Thus a vineyard where grassing is practiced favors the presence of these antagonistic insects.
To eliminate Lobesia botrana with biological control, we start from its careful monitoring.
Thus, trapping traps activated with the sexual aggregation pheromone will have to be placed inside the vineyards.
The monitoring traps must be placed in the vineyard from the beginning of April and replaced following the pheromone expiry indications. Generally, two traps are used per hectare of vineyard, so their cost is sustainable.
The trap allows to quantitatively understand the presence of the moth, so as to organize the interventions. It should be emphasized that, as a rule, no action is taken on first generation larvae.
In organic viticulture, the most effective product in the control of the vine moth is the bacillus thuringiensis.
In this sense, only the kurstaki variety is used, as the other bacillus varieties are ineffective on this parasite. It is a very selective bio insecticide, and is effective on Lepidoptera larvae in the first stages of life. It acts by ingestion, so it must reach the larvae of L. botrana before they enter the berries. For this reason it is used for second and third generation larvae.
For the second generation larvae, the bacillus thuringiensis is sprayed on the plants twice: the first time 7-9 days after the growing phase of capture in the traps; the second after 15-16 days (7 days after the first treatment).
To combat the third generation larvae, one action is taken only once, 14-21 days after the start of the captures with the monitoring traps. To improve the effectiveness of the bacillus against this butterfly, it is recommended to add about 1 kg of sugar for every 100 liters of water.
To summarize, therefore, the samplings must be carried out in three pre-established periods which more or less correspond to the three generations; in particular to flowering (the generation), from the thumbnail to the pre-closing of the bunch (2nd generation) and from veraison to the first half of September (3rd generation). With sampling, the intervention thresholds are:
– 1st generation: 35-50% of infested bunches;
– 2nd generation: it is possible to intervene at the first attacks on the grapes, in areas at risk; or with a threshold of 5% of bunches infested with larvae or in the presence of eggs or with penetration holes;
– 3rd generation: we intervene at a threshold of 5% of infested bunches.
Furthermore, preparations based on viruses and fungi (microbiological control) are being tested, which appear to have activity against some tortricides including Lobesia, and sexual confusion techniques.

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Russo G., 1976. Agricultural entomology. Special Part. Liguori Publisher, Naples.
– Pollini A., 2002. Handbook of applied entomology. Edagricole, Bologna.
– Tremblay E., 1997. Applied entomology. Liguori Publisher, Naples.
Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/126721660/original.jpeg