Agrivoltaics: current situation and next steps

In small fruit crops such as strawberries, blueberries, blackberries, raspberries and currants, various insects can cause significant damage to both the plant and the fruit. Here are the main ones:

The spotted wing drosophila Drosophila suzukii (Diptera: Drosophilidae), native to Southeast Asia, appeared in Europe in 2008 in Spain and Italy, subsequently spreading throughout the continent. In Italy, D. suzukii spread from north to south and to the islands in just a few years.

The Nematus ribesii is a sawfly belonging to the Tenthredinidae family. It is known as a parasite of gooseberries.

The Anthonomus rubi, known as the strawberry or raspberry weevil, is a small curculionid beetle that causes damage particularly to the flower buds of these species.

The Frankliniella occidentalis affects several species, including strawberries, where it causes brown streaks and deformation of the petals and malformation of the fruit. In the most severe attacks, the flowers may abort and the fruit may show browning and blackening of the achenes.

Aphids on small fruits (strawberries, currants, raspberries, etc.)

The Chaetosiphon fragaefoli sucks the sap from strawberry plants. The leaves and fruits become sticky due to the honeydew secreted, on which sooty moulds grow. It is also an important vector of several viruses that affect strawberries (Crinke virus, Mild yellow-edge virus).

The Yellow currant aphid (Cryptomyzus ribis) causes blistering and false galls on the edges of the leaves, which turn a wine-red colour. This damage spreads rapidly to other plants, hindering the development of the

The Cochineal is a small insect similar to aphids that feeds on the sap of currant plants. The honeydew it secretes spreads disease and dirties the berries, reducing their value.

The whitefly belongs to the order Hemiptera. Whiteflies belong to the Aleurodidae family; they suck sap and vector certain viruses. The sugary liquid excreted by the nymphs promotes the appearance of fungi such as sooty mould (a black fungus that disfigures affected plants) on the leaves.

Leaf-eating moths (Lepidoptera): their larvae can damage leaves and compromise blueberry development. The most common are the blueberry bush moth, whose larvae feed on leaves and shoots, and the blueberry moth, which mainly attacks the fruit.

The presence of defoliating moths can be seen by the remains of buds and flowers hanging from thin silk threads.

Beetles and mining larvae can damage blueberries. Adult beetles, such as the Japanese beetle (Popillia japonica), feed on leaves and flowers, causing damage to blueberry production. Mining larvae dig tunnels inside the leaves, and adults feed on leaves and flowers, affecting production.

La rete anti insetto è realizzata dalla tessitura di monofilo plastico e viene utilizzata per coprire e proteggere adeguatamente le colture dai danni causati dagli insetti, soprattutto la DROSOPHILA SUZUKI, la CARPOCAPSA e la CIMICE ASIATICA.

Il materiale utilizzato per la realizzazione delle reti anti insetto è il polietilene ad alta densità (HDPE). Il filo utilizzato è realizzato per estrusione, fondendo e facendo passare attraverso delle griglie forate (estrusori) la materia prima; successivamente viene termostabilizzato, ovvero viene riscaldato per far diminuire tutte le ritrazioni che normalmente presenta il materiale plastico esposto a fonti di calore anche modeste.

La rete antinsetto è realizzata lavorando il monofilo con una particolare tecnica chiamata tessitura a telaio: la maglia che si ottiene con questo tipo di lavorazione è di forma rettangolare di misura variabile ed è indeformabile, cioè le dimensioni non variano quando il telo anti insetto è sottoposto alle sollecitazioni.

Le reti anti insetto sono disponibili nelle seguenti dimensioni:
Rete ANTI-CARPOCAPSA: H 2,50 – 4,00 – 4,60
Rete ANTI-SUZUKI: H 2,00 – 2,50 – 3,00

Actinidia (kiwi) cultivation can be threatened by various phytophagous insects, some of which cause direct damage to the fruit, while others weaken the plant, making it more vulnerable to disease. Here are the main ones:

Argyrotaenia pulchellana (Eulia) is a polyphagous leaf-rolling moth that feeds on the leaves, flowers and fruit of numerous herbaceous and arboreal plants, both cultivated and wild.

Metcalfa pruinosa is a homopteran insect belonging to the Flatida family. It can attack kiwifruit, sucking sap and producing white waxy secretions, expelling the sugary part as honeydew and causing the development of sooty moulds, which facilitate the growth of harmful fungi that cover the leaves and fruit with a black coating, reducing photosynthesis and growth.

Pseudaulacaspis pentagona (white scale insect) can cause damage by piercing the shoots of actinidia, causing stress and weakening the plant. In the most serious cases, the branches dry out and fruiting is compromised. Affected fruit develop a reddish halo around the follicles, causing serious economic damage, as they cannot be sold or exported.

Empoasca vitis (green leafhopper) pierces the leaves of actinidia, altering lymphatic flow and transpiration and causing yellowing that rapidly spreads from newly formed leaves to older ones. Necrosis begins at the edges of the leaves, which then fall off, causing a reduction in photosynthesis.

Panonychus ulmi (red spider mite) can infest kiwifruit in hot, dry weather conditions. Repeated bites from the mites reduce the functionality of the foliage, causing leaf discolouration, premature leaf fall and general weakening of the affected plants.

Autographa gamma: The larvae of these lepidoptera can cause significant damage to actinidia plants as they feed on leaves and shoots, the loss of which reduces and may affect photosynthetic capacity, leading to a subsequent reduction in fruit production and quality.

Halyomorpha halys is an extremely polyphagous species that also affects actinidia plants. In spring, the adults colonise the plants, feed and lay their eggs. The larvae, which go through several stages of development, also feed on the sap of the plants and fruits, causing them to fall and become deformed, thus compromising their marketability.

THE MAIN DISEASES AFFECTING CHERRY TREES – PRUNUS AVIUM

MONILIA DISEASE OF THE CHERRY TREE

Monilia is one of the most widespread and easily recognisable diseases affecting cherry trees. It is caused by two different parasites, called Monilia laxa and Monilia fruttigena, which thrive in particularly damp soil and when the plant is not pruned and disinfected correctly.

The most dangerous period is spring, when temperatures begin to rise and irrigation may be more abundant, with a higher risk of liquid accumulation and stagnation, which causes the fungus to proliferate.

It is easy to recognise when the leaves, flowers or fruits suddenly become darker, as if covered with a thick, compact layer of grey mould, which tends to rot them from the outside inwards and cause them to fall off.

The branches appear dry, with cracks that are an indication of the disease, inside which spores proliferate and where other variants of different bacteria can also insidiously develop.

CORINEO DISEASE OF THE CHERRY TREE

Corineo is also commonly referred to as shot -hole disease, precisely to emphasise how the disease manifests itself with small spots that tend to affect every part of the plant, starting with the leaves.

The characteristic colour of these anomalies is a reddish-purple that forms a distinctive halo that spreads across the entire surface, causing the leaf or fruit to fall and die.

The disease can also be recognised by the small holes that form inside the halo, as well as on the branches near the buds, which are unable to blossom and therefore transform.

The cherries also show encrustations that are difficult to remove and prevent the fruit from being edible.

This is another fungal disease that occurs mainly in spring, when the temperature is very humid and the spores find fertile ground for proliferation.

BACTERIA CANCER OF THE CHERRY TREE

The name sounds rather threatening, and indeed this is one of the most dangerous diseases that can affect this variety.

In this case, it is not caused by a fungus but by a bacterium, which likes to nestle in various types of stone fruit and lead to their premature death, first drying out the branches at the ends and then reaching the heart of the tree and its roots.

The symptoms of bacterial cancer are dark spots that appear irregularly on the leaves, with lighter, blurred halos and necrotic parts on woody areas such as branches and the trunk.

THE ROTTEN CHERRY TREE

Rottenness is one of the most common diseases affecting cherry trees and is caused by a number of factors.

The first factor is excessive irrigation of soil that is already very moist, which causes puddles and waterlogging, leading to the deterioration of the roots as they extend upwards.

The second factor is certain types of fungi, which manifest themselves in this way and must therefore be treated with sulphur-based products and other antibacterial and antiseptic agents. One of the fungi that most affects cherry trees in the Vignola area and is already present in Puglia is Armillaria mellea, a fungus that appears on the roots with a whitish colouring that can lead to the death of the plants. This is more prevalent in soils where cherry trees have been cultivated for a long time.

To prevent this phenomenon, it is therefore advisable to pay attention to soil preparation, adjusting watering according to weather conditions and pruning dry and diseased parts tactically to prevent them from damaging the fruit.

LEAF SPOT DISEASE OF THE CHERRY TREE

Also known as leaf blight, this disease tends to occur mainly in summer and is caused not by a lack of water, as one might mistakenly think, but by a fungus called Gnomonia erythrostoma.

This misunderstanding often leads to delayed action, but it is possible to recognise the difference by noticing yellow patches with a red halo around them, which tends to darken when the necrosis is already at an advanced stage.

The dry leaf tends to fall off, leaving the plant bare.

As with any other infection of this kind, the key is to use a sulphur-based product or the classic copper sulphate to stop the spores from spreading, taking care to remove any damaged parts that are beyond repair and will only encourage the disease to spread.

LEAF-RUST DISEASE OF THE CHERRY TREE

Similar to the previous disease in terms of symptoms, this disease manifests itself with brownish spots mainly on the upper side of the leaf, which gradually darkens until it dies and falls off.

The disease then spreads to the branches, preventing the buds from blooming and thus preventing fruit formation.

The white pustules that accompany this condition can be defeated with a copper-based spray, which is disinfectant and antifungal, combined with a sulphur component for a stronger action.

BLACK APHIDS ON THE CHERRY TREE

This is a disease that can be easily recognised, as it develops following infestation by small black insects that are visible to the naked eye.

These insects bite the shoots of cherry trees and other fruit trees, depositing a large number of other young aphids that do the same thing.

The tree will die quickly if immediate action is not taken, resulting in small, deformed and inedible cherries.

The only solution is to use a specific insecticide or have the tree professionally treated by a pest control expert.

In cherry orchards, various insects can compromise the quality and yield of cherries. Here are the main pests to watch out for:

• Spotted wing drosophila (Drosophila suzukii): attacks ripe fruit, laying eggs and causing damage similar to that caused by cherry fruit flies.
• Cherry fruit fly (Rhagoletis cerasi): lays eggs in the fruit, and the larvae that emerge feed on the pulp, causing rot and turning the fruit unsuitable for sale.
• Aphids (especially Myzus cerasi): feed on the sap of leaves and shoots, causing deformities and sticky secretions (honeydew) that can cause mould to develop.
• Cydia funebrana and Cydia molesta: two species of moths, known respectively as the plum moth and the oriental peach moth. Cydia funebrana is a moth that mainly attacks plum trees, but can also affect other stone fruits. The Cydia molesta moth is considered one of the most harmful pests for fruit trees in Emilia-Romagna.
• Cochineals: these scale insects are parasites that feed on sap, causing stunted growth, yellowing of leaves and defoliation. They are covered with waxy secretions and come in several types: “powdery”, “soft” and “armoured”.
• Thrips (Thysanoptera family): attack flowers and fruit, deforming them and causing phylloptosis or even compromising flowering and fruiting.
• Asian bug: although not specific to cherry trees, the Asian bug can damage fruit by piercing it and sucking out the sap, causing deformities and bruising.
• Peach twig borer (Anarsia lineatella): this is a moth belonging to the Gelechiidae family. Its larvae initially settle in the shoots and then in the fruit. It mainly affects peach trees but also settles on other stone fruits (apricot trees, etc.).

Valente offers a quick and automatic system that allows rain covers to be opened and closed like an umbrella, for optimal cherry orchard management.

This innovative technology, installed exclusively on the Multishield structure, offers great advantages and represents a complete, effective, flexible and safe solution for farmers to protect their crops.

The particular arrangement of the Multishield system's covers allows the operator to slide them along the frame of the structure, so that they can be opened and closed as needed, with the great advantage of allowing the plants to grow in normal conditions for most of the time, covering them only when necessary, i.e. when there is a real risk of rain, thus promoting the best development.

The Valente system makes this operation quick and effective, allowing a single worker to close or open the cover much faster than manual systems.

Peach and apricot orchards are susceptible to various harmful insects that can compromise the quality and quantity of the harvest.

On peach trees, damage is mostly during harvest time; attacks during flowering and fruit set only happen in protected crops, while they are rare for open field crops. The damage is only cosmetic and shows up as discolouration of the skin, mostly on nectarine cultivars, where it can seriously depreciate the product.

Insects

• The oriental moth (Cydia molesta), also known as the oriental peach moth, is a lepidopteran that mainly infests stone fruits (peaches, apricots, plums, cherries) and, to a lesser extent, pome fruits (apples, pears). The larvae of this insect dig tunnels in shoots and fruits, causing deformities and rot.
• The peach twig borer (Anarsia lineatella) belongs to the order Lepidoptera. It mainly damages peach trees, but also apricot, plum and almond trees. The larvae of this moth burrow into young branches and fruit, causing the shoots to wither and the fruit to become deformed.
• The fruit fly (Ceratitis capitata), also known as the Mediterranean fruit fly, is a harmful pest for many fruit crops. Adult females lay their eggs inside ripening fruit and the larvae feed on the fruit pulp, digging tunnels that favour the development of mould and bacteria.
• Aphids feed on plant sap, weakening plants and deforming leaves and shoots. Although they do not attack ripe fruit, they weaken the plant, which produces smaller and damaged fruit. They can also be vectors of viral diseases.
• Scale insects attack peach and apricot trees, weakening the plants. White peach scale insect: found on leaves, fruit and branches. Affected fruit has a reddish halo around the follicles. San Jose scale: causes reddish spots with a dark centre and forms encrustations on branches. Cotton scale: damages branches and causes yellowing of leaves. The honeydew they produce causes the development of sooty moulds that smear the fruit, making it unmarketable.
• Thrips cause damage to the fruit and leaves of peach and apricot trees. The punctures on the fruit cause deformation and cracking, while on the flowers they cause dripping and can induce fruit drop, as well as causing necrosis and deformation of the leaves.
• Yellow and red woodworms attack peach and apricot trees, digging tunnels in the branches and trunk, weakening the plants and making them susceptible to breakage and secondary infections. The yellow woodworm (Zeuzera pyrina) is characterised by the yellowish colour of its larva, which burrows tunnels in the branches and trunk, causing the shoots to dry out and, in severe cases, causing the branches to break and making them susceptible to fungal attacks.

The use of orchard coverings, now common practice for most crops grown using modern farming methods, actually has a fairly recent history. In the 1960s, when our company entered the market with the production of pre-stressed reinforced concrete poles, the idea of covering orchards was certainly not a priority for farmers, but, as is now clear, many things have changed in just over 60 years.

Starting in the 1980s, besides hail protection, other needs emerged such as protection from insects, rain, wind and sun.

Thanks to the experience we've gained over the years, two other new aspects have emerged that are proving to be fundamental.

The first is that these coverings, in addition to fulfilling their specific functions, can actually be multifunctional, i.e. capable of performing multiple tasks and offering different types of protection.

The second is that coverings also guarantee a better microclimate for crops in various ways, creating a more favourable environment for plant growth and increasing fruit productivity and quality.

Scientific literature on this subject is now quite extensive and, although necessary distinctions must be made regarding the type of coverings, cultivation and characteristics of different territories, it agrees on confirming the benefits in relation to the following parameters.

• Temperature:
  • Coverings help maintain a more stable temperature in the environment below, reducing extreme fluctuations.
  • During the summer months, the temperature under the coverings is lower than in uncovered areas, which helps reduce heat stress on plants.
  •  Conversely, during the winter months (especially the coldest ones), the temperature under the tensile structures tends to be higher than in the open air, thanks in part to their protection from the wind.
• Humidity:
  •  The relative humidity under the coverings is slightly higher than in uncovered areas, favoring a more humid microclimate that has proven beneficial for crops.
  • o his increase in humidity helps reduce transpiration and water loss from plants, improving water use efficiency and promoting root growth.
• Light:
  • Coverings reduce direct light intensity by filtering sunlight and distributing it more evenly.
  • This leads to a reduction in sunburn on fruit and better use of photosynthetic light, which is essential for plant growth.
• Fruit Productivity and Quality:
  • Coverings help improve fruit quality by reducing physical damage caused by hail
  • In addition, fruit harvested under coverings shows greater uniformity in terms of size and ripeness and a higher overall yield

These are vital benefits, especially when we consider that the environmental situation is continuing to evolve and become more complicated, with mild winters and late frosts, concentrated and more intense rainfall, frequent hailstorms, excessive wind and sunlight, and an increase in alien pathogens.

This scenario leads to one conclusion: fruit growing without orchard covering systems is now unimaginable.

Obviously, there are different types of solutions, from traditional anti-hail systems to multifunctional ones complete with insect nets, single-wire or monobloc systems with different levels of automation, but all of them have a positive impact. Despite representing a significant initial investment, they bring long-term benefits in terms of improved quality and quantity of production that more than justify the costs.

In apple and pear orchards, various insects and fungi can cause significant damage to both the plants and the fruit. Here are the main ones:

Apple tree

• Codling moth (Cydia pomonella), also known as the “apple worm”, mainly attacks pome fruits (apple and pear trees) but also causes damage to other fruit trees (peach trees, etc.). The larva burrows into the fruit, causing it to rot. If left untreated, it causes very serious damage to production.
• Aphids (Aphis pomi, etc.). Apple and pear aphids belong to the species Aphis pomi (green apple aphid). Aphids feed on sap, causing leaves and young shoots to curl. Severe attacks can compromise growth and fruit production, especially on young plants.
• Tortricidae (Pandemis heparana, Adoxophyes orana): this is a moth known as the green apple leaf roller, which has two generations per year and overwinters as a larva in the bark at the end of the second generation. They attack vegetation and fruit, damaging them.
• Red spider mite: Panonychus ulmi (red spider mite) attacks pome fruits and other fruit species. It bites the foliage, causing discolouration and premature leaf fall and weakening the affected plants.

Pear Tree

• Psilla (Cacopsylla pyri). A scale insect that sucks the sap from leaves and shoots, causing deformities that compromise the plant. It can cause phylloptosis and flower death. Psyllids also produce honeydew, which promotes the development of sticky sooty moulds that cover the plant's organs. It is characterised by a high reproductive capacity (several generations per year and lays over 500 eggs at a time).
• Aphids: Small insects that suck sap, weakening the plant and promoting the spread of disease.
• Hornworm (Hoplocampa testudinea): The larvae of this insect attack developing fruit, causing damage similar to that of the codling moth.
• Cecidomia: a dipteran (fly) that causes galls to form on leaves and fruit, compromising their marketability.
• Asian bug: an insect recently introduced into our environment that attacks many species of fruit. It causes severe damage to pear trees by stinging and deforming the fruit, which is then no longer marketable. Having been introduced from Asia, it has no effective predators that can control its development in our environment.
• Drosophila suzukii: pome fruits are not its primary hosts, but its larvae can penetrate the fruit, damaging it and affecting its marketability.

Mushrooms

The most common fungal diseases affecting apples and pears are:

• Scab: scab (Venturia inaequalis and Venturia pirina) causes spots on leaves and fruit, deforming them and compromising their quality and, consequently, their marketability.
• Powdery mildew: powdery mildew (white mould), caused by Podosphaera leucotricha, affects leaves, flowers and fruit. Infected flower buds turn silvery-white and hatch later than healthy ones. The petals appear distorted of a pale green colour. The flowers appear crumpled and do not produce fruit.
• Branch canker: (Neonectria galligena): produces depressed marks on the bark, which develop into cankers with cracking and necrosis. The plant reacts by healing the lesion, but the healing tissue is also attacked, forming open cankers that expose the woody tissue.
• Rot in pome fruits: moniliosis and pink rot are fungal diseases that affect apples, pears and other fruits. Moniliosis, caused by Monilia fructigena, causes fruit rot, cankers on branches and desiccation of flowers and shoots. Pink rot (Trichothecium roseum) causes grey-brown spots that can affect the flesh of the fruit.

• Brown spot of pear trees (Stemphylium vesicarium) causes brown necrotic spots on leaves, fruit and shoots, with serious damage and rot. The most important cultivars are particularly vulnerable (Abate Fétel, Conference, Decana del Comizio, Kaiser, etc.).
• Gummosis (Cytospora spp.) is a fungus that affects pome fruits, causing lesions on the bark, resinous discharge and necrosis of the bark. It mainly affects weak or stressed trees.
• Valsa ceratosperma: causes cankers similar to those of branch canker, with swelling of the bark and blackish spots. It occurs on branches, twigs and trunks with cankers that create cracks and a clear separation between healthy and diseased parts. When the canker has surrounded the affected part, the distal part dies and if this occurs in the lower part of the trunk, the plant is compromised.
• Peach leaf curl (Taphrina spp.): normally found on peach trees but it can also be found on apple trees; it damages the foliage.