Necessary deletion

The South American fruit fly Anastrepha fraterculus (Wied., 1830) (Diptera: Tephritidae) is the main pest of temperate fruit trees in the Southern Region of Brazil. Management of the species has been carried out mainly by spraying insecticides to control adults and larvae located inside the fruits. However, the main insecticides used in these applications (fenthion, trichlorfon and methidathione) have been withdrawn from the Brazilian market or are in the final phase of commercialization due to toxicological restrictions.

One of the alternatives to reduce pest infestation in orchards is the use of toxic baits, a technology that has as its principle the association of a food attractant with an insecticide (generally organophosphate or spinosyn) applied in bands, mainly on the edge of the orchards, with the objective of reducing the infestation of the pest that normally moves into production areas (Figure 1).

Figure 1 - Aerial image of an apple orchard located in the municipality of Antônio Prado, RS. The red color indicates locations with the highest captures of South American fruit fly adults in the 2012/2013 harvest. Source: Frighetto et al. (2013). Composition using images from with Google Earth

Based on the information that female fruit flies need to ingest carbohydrates and proteins to complete the development of the reproductive system and the maturation of eggs, an attempt is made, with the use of toxic baits, to reduce the adult population and consequently prevent mating (by eliminating males) and oviposition of females.

One of the first records of the use of toxic baits in the management of fruit flies occurred in Hawaii in 1952, where brown sugar (food attractant) mixed with the insecticide parathion was applied to guava trees to control fruit flies. Mediterranean Ceratitis capitata (Wied., 1824) (Diptera: Tephritidae). In Brazil, the first report of applications of toxic baits to suppress the fruit fly population occurred in 1973 in citrus orchards in São Paulo, and in the south of Brazil, the use of this technological tool occurred in 1979 in apple cultivation. . Currently, liquid sugarcane molasses has been the attractant most used by fruit growers (Figure 2).

Figure 2 - Food attractants used in the preparation of toxic baits for the control of South American fruit flies in apple cultivation in Vacaria, RS (columns in black), and São Joaquim, SC (columns in gray). Source: Pink et al (2013)

Studies conducted in different regions of Brazil demonstrate that toxic baits are effective in reducing the population pressure of the pest in production areas. However, this technology has not been a common practice among fruit growers in the Southern Region of Brazil. Among the main reasons for the low use of technology, the following stand out: 1) the need for weekly reapplication due to the low persistence of toxic baits after rainfall; 2) the need for labor and modifications to conventional spraying equipment; 3) the risk of harmful effects on natural enemies and pollinators, especially when sugarcane molasses is used with organophosphate insecticides; 4) the offer on the market, until recently, of organophosphate insecticides with deep action proven to be effective for controlling the pest. Another restriction for applying the technique is the report from some producers, especially those who grow fruit in small areas (up to two hectares), that the baits can attract a greater number of adult fruit flies into the orchard. , which would increase the risk of damage caused by the pest. However, this hypothesis needs to be confirmed.

The use of attractants based on sugars and hydrolyzed proteins associated with an organophosphate insecticide mixed at the time of application has practically not evolved since the 1950s. In 2006, the first ready-to-use toxic bait formulation (Success) was introduced into the Brazilian market. * 0,02 CB) containing new attractants and the biological insecticide spinosad. This formulation was developed to control fruit flies adults and presents greater selectivity to natural enemies and pollinators. Currently, the product is used in practically all official fruit fly control programs, and is even authorized for organic production in several countries.

However, in Brazil, according to the Pesticides, Components and Related Legislation, the registration of formulated products is carried out for the target crop and not for the pest species. Therefore, the use of this ready-to-use formulation is restricted to citrus, mango, cherry and vine crops, in addition to official programs, such as the carambola fly. Bactrocera carambolae (Drew & Hancock, 1994) (Diptera: Tephritidae). This fact prevents the use of the formulation on fruit trees in temperate climates. Furthermore, there is no offer of an easy-to-operate application technology for using the product in low volume (2L/ha to 4L/ha) in addition to observing phytotoxicity when applied to apple and peach crops (Figure 3).

Figure 3 - Phytotoxicity symptoms caused by the application of Success* 0,02 CB toxic bait on apple (left) and peach (right) leaves. Photos: Cesar Boff

In 2012, a new food attractant (Anamed) was launched on the market to be used in toxic baits to control the South American fruit fly. The attraction is based on Splat technology (Specialized Pheromone & Lure Application Technology) and is characterized by containing attractants and feeding stimulants, in addition to compounds that extend the useful life of the formulation that must be associated with an insecticide in an “attract-kill” strategy (Figure 4). In the same way as Success* 0,02 CB, the formulation should only be applied to the edges of production areas, so that the product does not come into contact with leaves or fruits, as the formulation is also phytotoxic (Figure 4).

Figure 4 - Anamed (bottom left) and phytotoxicity in apple fruit after application of the toxic bait containing the attractant. Photos: Jardel Talamini de Abreu

One of the main advantages of the Anamed attraction compared to other formulations available on the market is related to greater resistance to rain and less degradation by solar radiation. This provides greater efficiency in controlling fruit fly adults than traditional formulations, especially in places with high rainfall frequency, such as those located in the Southern Region of Brazil (Figure 5).

Figure 5 - Cumulative mortality of South American fruit fly adults Anastrepha fraterculus 72 hours after supplying toxic baits subjected to rain at intensities of 20mm (black columns) and 50mm (gray columns) using an artificial rain simulator. Bento Gonçalves, RS. Source: adapted from Borges (2011)

Another advantage of this attraction is linked to the safety of the formulation. The product causes lower mortality of an important natural enemy of the fruit fly [the parasitoid Diachasmimorpha longicaudata (Ashmead, 1905) (Hymenoptera: Braconidae)] and also has a repellent effect on adults of Apismellifera L. (1758) (Hymenoptera: Apidae) (Figure 6), which causes the pollinator to be removed from the point or location of the bait application. All these advantages make the attractant an important alternative for managing fruit flies.

Figure 6 - Average number of visits Apis mellifera in artificial foraging stations containing the food attractant with and without the insecticide malathion [Malathion 1000 EC (0,15%)] over nine daily image shots. São Joaquim, SC, 2014. ^ns not significant between treatments in each assessment. Source: Pink et al (2014)

Experiments conducted in commercial orchards with the aim of validating the toxic bait Anamed + organophosphate insecticide applied to the edges of the orchard (1,5kg/ha) provided superior efficacy to sugarcane molasses, an attractant currently used by fruit growers.

Table 1 - Main characteristics of toxic baits available on the Brazilian market

Toxic bait(formulation)	Attractive	Insecticide	Selectivity¹	Resistance to rain²	Phytotoxicity³
Ready to use	Success* 0,02 CB	Spinosad	Media	Low	Yes
Prepared on the property	Sugar cane molasses	Organophosphate	Low	Low	No
	Hydrolyzed protein (Biofruit)	Organophosphate	Low	Low	No
	Anamed	Organophosphate	High	High	Yes

Toxic bait(formulation)

Attractive

Insecticide

Selectivity¹

Resistance to rain²

Phytotoxicity³

Ready to use

Success* 0,02 CB

Spinosad

Media

Low

Yes

Prepared on the property

Sugar cane molasses

Organophosphate

Low

Low

No

Hydrolyzed protein (Biofruit)

Organophosphate

Low

Low

No

Anamed

Organophosphate

High

High

Yes

¹Selectivity to the parasitoid Diachasmimorpha longicaudata e apis melifera.

² Resistance to washing by rain above 5mm.

³Symptoms of phytotoxicity on leaves and fruits in temperate fruit trees and vines.

Throughout the harvest, population monitoring of fruit fly adults indicated the occurrence of higher population peaks in areas with conventional management (toxic bait prepared with sugarcane molasses + insecticide) compared to those managed with Anamed + insecticide ( Figure 7).

Figure 7 - Population fluctuation of South American fruit flies adults in apple orchards during the 2012/2013 harvest, managed with application of sugarcane molasses + organophosphate insecticide (dotted line) and Anamed + organophosphate insecticide (solid line). Vacaria, RS. Source: Machota Jr et al - unpublished data (dnp)

At harvest, a reduction in the percentage of fruits with the presence of South American fruit fly larvae was recorded in areas managed with Anamed compared to others managed with sugarcane molasses (Figure 8).

Figure 8 - Percentage of fruits with the presence of South American fruit fly larvae Anastrepha fraterculus during the 2012/2013 harvest. The dates refer to the harvest in apple orchards of the Gala, Fuji and Pink Lady cultivars, respectively, managed with the application of sugarcane molasses + organophosphate insecticide (white columns) and Anamed + organophosphate insecticide (black columns). Vacaria, RS. Source: Machota Jr et al - dnp

In peach cultivation, with the use of the Eragil cultivar, a significant reduction in adult captures of South American fruit flies was recorded in areas where the toxic bait Anamed was used associated with cover applications when compared to conventional management. only with sprays of organophosphate insecticide in coverage (Figure 9). This effect would be associated with the reduction in the population of adults that invade the orchard caused by the application of the toxic bait, reducing population growth close to fruit maturation/harvest.

Figure 9 - Population fluctuation of adults in Anastrepha fraterculus in two peach orchards of the Eragil cultivar in the municipality of Farroupilha, RS, during the 2013/2014 harvest. Management with sequential application (15-day interval) of organophosphate insecticide in the total area (dotted line) compared to management with application of Anamed + organophosphate insecticide in coverage (solid line). Farroupilha, RS. Source: Machota Jr et al - dnp

In this experiment, the average number of peach fruits from the Eragil cultivar with peach larvae A. fraterculus in the conventional area and with the application of Anamed toxic bait it was 77,8% and 6,6%, respectively. These results demonstrate that the use of toxic baits reduces damage from fruit flies in the harvest when compared only to spraying with insecticides in the total area and that there are different attractant options that can replace sugar cane molasses in crop management. Prague.

Application Technology

The technology for applying toxic baits is still the main challenge that hinders the adoption and expansion of this fruit fly management strategy by fruit growers. In the case of Anamed, the application has been carried out with a Sthil model BR420 gasoline leaf blower attached to the back of a motorcycle seat and adapted to apply the toxic bait (Figure 10). Video preview available at http://www.youtube.com/watch?v=lGgCzWoIPUA.

Figure 10 - Experimental model of toxic bait applicator composed of a Sthil model BR420 gasoline leaf blower attached to the back of a motorcycle seat. Photo: Rafael Borges

Another applicator model is the Sthil model BG86 C-E gasoline leaf blower (Figure 11). The advantage of this model is its reduced weight (4,5kg) compared to the previous model (9,1kg), making it easier to transport the equipment manually, and can also be used on a tractor or other means of transport (Figure 12).

Figure 11 - Anamed toxic bait applicator with emphasis on the toxic bait deposit funnel (1) and the flow control valve (2). Photo: Ruben Machota Junior

Figure 12 - Application of the toxic bait Anamed on the edge of a peach orchard. Photo: Marcelo Zanelato Nunes

With the withdrawal of the main organophosphate insecticides effective in controlling fruit flies from the market and the increasing pressure for the absence of residues in fruits, techniques for population suppression of adult fruit flies, mainly the use of toxic baits , are essential to reduce infestation in orchards. In order for the use of toxic baits to be expanded, there are different formulations available on the market (Table 1) allowing farmers to employ this technological tool in orchards following an integrated management strategy.

This article was published in issue 87 of Cultivar Hortaliças e Frutas magazine. Click here to read the edition.