FEATURED INFORMATION

Grapevine Pest Management in Chile

Luis Sazo Rodríguez

Plant Health Department. University of Chile

Official 2013 figures show that vineyards cover 58.9% of all land used for growing fruit in Chile, which totals 300,061 hectares, including pome, stone and citrus fruit orchards, avocado trees, and walnut trees. 125,946 hectares are planted with grapevines for wine production, mostly for export as bottled or bulk wines, the main markets being North America and the United Kingdom. Table grapes are grown on 53,727 hectares, mainly for export to North America, Asia, Europe and Latin America.

Official 2013 figures show that vineyards cover 58.9% of all land used for growing fruit in Chile, which totals 300,061 hectares, including pome, stone and citrus fruit orchards, avocado trees, and walnut trees. 125,946 hectares are planted with grapevines for wine production, mostly for export as bottled or bulk wines, the main markets being North America and the United Kingdom. Table grapes are grown on 53,727 hectares, mainly for export to North America, Asia, Europe and Latin America. The main challenge faced by the wine sector is to produce quality wines free of pesticide residue; for this reason, a number of winemakers targeting export markets have special requirements in terms of the active substances that can be used in a plant protection program, and some even place arbitrary restrictions on the use of pesticides, particularly in the 60 days prior to harvest. The table grape industry, for its part, while complying strictly with the residue limits placed on it by various markets, faces an additional restriction in the form of zero tolerance of certain organisms, the presence of which could block the import of the fruit, particularly to Asian and Latin American markets.

There are relatively few pests of economic importance affecting grapevines, with major differences to be found between wine grapes and table grapes, which is logical, considering the nature of the final product.

For wine grapes, the main pest species is Brevipalpus chilensis (Acarina: Tenuipalpidae), a native mite and a key pest affecting red wine varieties such as Cabernet Sauvignon, Merlot and Carmenere and white wine varieties such as Chardonnay. This species hibernates as an adult female and can complete up to five generations in a single season. It attaches to the underside of the leaf and can have an especially deleterious effect on Cabernet Sauvignon, where it can cause the shoots to completely dry out at the start of the season. There are few natural controls, as the predator mite Neoseiulus californicus (Acarina: Phytoseiidae) present in these agricultural ecosystems does not tend to prey on this pest. For this reason, pest control takes the form of the application at budding of specific acaricides with different modes of action, such as acrinathrin, acequinocyl, spirodiclofen and even paraffin oil, which can also be used to treat powdery mildew. Early control is more effective and therefore preferable, due to the ease in coating the full leaf as well as the reduced cost and environmental impact.

The other species to have taken on economic importance, particularly for vineyards, in the past three years is the European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae). First reported in April 2008, and despite programs to eradicate it, the pest has now taken hold in a number of production units in central Chile, in an area covering 300 km. The transport of fruit from infested areas to non-infested areas, the use of pesticides with little effect on the pest, and the lack of a broad-based management program for domestic vineyards bordering on production units are the main reasons behind this worrying increase in the pest population over the past three seasons. The official pest management strategy, applicable only in those areas where the pest has been detected, calls for two insecticide applications on the first and second generations and a single application on the third generation. In areas where the species has become established, mating disruption techniques are employed, using mainly Isonet L, in addition to the insecticide applications described above. It is worth noting that this latter strategy was the one that was successfully used in the first two seasons of the eradication program. The main difference may lie in the type of insecticides used on that occasion: the pesticides were selected on the basis of the products being registered for this use in Europe and demonstrating clear, effective action against the pest. Currently, a number of insecticides are being used successfully against this pest: flufenoxuron, fenoxicarb, diflubenzuron, phosmet, methoxyfenocide, spinosad, chlorantraniliprole and others. Biological insecticides of the Bt group have a limited effect on this pest.

The presence of Lobesia in table grapes is also cause for concern. Despite low infestation levels of Lobesia, given the quarantine status of this pest, the very fact of vines being located in infested areas threatens grape shipments to markets in Asia and Latin America, such as Mexico, as these markets have clearly stated that they will not purchase fruit from infested areas. To conclude, this season has seen two new developments related to the presence of this pest in Chile. In the course of plant health inspections, Lobesiawas detected first in cherries and then, even more importantly, in blueberries. While both fruit species are currently considered to be temporary hosts only, these developments have been taken so seriously that the United States, the main importer of blueberries (with 70% of the market), has announced through APHIS that all fruit must be fumigated at origin before being allowed onto the market. This action will shorten postharvest shelf-life and thereby reduce export business.

In table grapes, different pests are considered to be of economic importance. Besides Lobesia in the regions mentioned, there are the pests Frankliniella occidentalis (Thysanoptera: Thripidae) as well as the Pseudococcus complex, in particular P. viburni(Hemiptera:Pseudococcidae), which is the main cause of rejection of lots in plant health inspections of fruit in Chile.

F. occidentalis
was first reported in 1995. That year, there was a major drought leading to the loss of the entire harvest for certain varieties of nectarine and table grape. This pest, which has a broad distribution in the central, southern and even northern regions of the country, is considered to be a key pest for these fruit crops as well as for cherry and peach. It requires rigorous, regular management in critical periods using specific insecticides; in the case of nectarines, complementary cultural methods must be employed, such as leaf removal and shoot thinning, to limit infestations of fruit. In table grapes, major damage has been detected at flowering (halo spots), particularly in white varieties but also in colored varieties such as Red Globe, where the grape berries break at oviposition sites. Another worrying development is the increased observation of damage caused after fruit set, which takes the form of a ring-shaped mark where the grapes touch, especially in the inside parts of the bunch. One to four applications are customary during flowering, depending on how long the stage lasts. Spinosad is the pesticide most commonly used, as well as acrinathrin or bifenthrin when the waiting periods for the destination markets permit. After fruit set, spinosad tends to be used for this same reason, and tends to be required for units bordering on hillsides or areas with abundant natural vegetation.

It is also worth noting that in the past three years, there have been studies examining the effect of the use of mineral and vegetable oils on stone fruit (nectarine and cherry) trees, the idea being to reducing the damage caused by F. occidentalis through preharvest applications. Similar studies have been launched this season for table grapes, examining how to reduce the damage caused by this insect in the post-set period.

Another major table grape pest is P. viburni. It is considered a key pest for this crop. It can be found in more than 90% of all vineyards in Chile. It infests the aerial part of the plant, and even underground parts around the collar. It is associated with a number of weeds common to these agricultural ecosystems, the main ones being field bindweed (Convolvulus arvensis), wild tomato (Physalis angulataL), Indian strawberry (Duchesnea indica (Andr.) Focke) and cheeseweed mallow (Malva parvifloraL.). It is also found in tree species such as black locust (Robinia pseudoacacia) and a number of ornamental species; all of these constitute a major source of infestation of productive units. There are many natural enemies associated with this insect, as described in the literature; however, they are not found in units under regular treatment, which is why management of this pest requires the use of insecticides combined with certain farming methods, e.g. the practice of trimming leaves, especially for wine grapes. P. vuburni hibernates mainly in the egg stage and completes three generations per season. The second and third may even occur within the grape bunch. The first generation generally develops under loose bark, feeding directly on the phloem, or in shady, damp parts of the plant. Detection of egg sacs or live individuals during plant health inspections is the main cause of rejection for certain markets, as the direct damage caused by feeding is irrelevant. Management of this pest is based on a program of (two or three) postharvest applications of synthetic organophosphates such as chlorpyrifos, the use of which is restricted preharvest; diazinon; and even certain growth regulators such as buprofezin, which only controls juveniles, as well as springtime applications of spirotetramat during the post-set stage.

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Data protection policy

In accordance with the Organic Law on the Protection of Personal Data 15/1999, of 13 December, Promotora de Exportaciones Catalanas SA (hereinafter PRODECA), whose address is Gran Via de les Corts Catalanes, 620, principal, 08007 Barcelona, with tax reg. no. NIF A58241316, declares that the images contained on the website www.smartfruitcongress.cat are included in a file belonging to PRODECA. The purpose of this file is the promotion, via its website, of the activities conducted by PRODECA – SmartfFruit IPM International Congress.

PRODECA guarantees that you may, at any time, exercise your right to access, rectify, cancel or oppose by writing to the aforesaid postal address, using the reference "PROTECCIÓN DE DATOS - SMARTFRUIT", or to the email address smartfruitcongress@smartfruitcongress.cat.

Specifically, to correctly exercise these rights you must clearly provide the following items in that communication:
- Name, surname(s) and photocopy of National Identity Document or Passport.
- Statement of the purpose of the request.
- Address for notification purposes.
PRODECA also declares that it reserves the right to delete from its website any content that it considers violates current and applicable legislation.

D’acord amb l’article 17.1 de la Llei 19/2014, la ©Generalitat de Catalunya permet la reutilització dels continguts i de les dades sempre que se'n citi la font i la data d'actualització i que no es desnaturalitzi la informació (article 8 de la Llei 37/2007) i també que no es contradigui amb una llicència específica.