Resistance to the attack of Bactrocera oleae (Gmelin) of some Sicilian olive cultivars

Genetic resistance of olive germplasm could be an important tool in the control of Bactrocera oleae (Gmelin), the key pest in the Mediterranean olive growing. Up to now, no study was carried out on olive cultivars stressed a complete resistance to the attack of B. oleae, and few scientific data are available on susceptibility to olive fruit fly of Sicilian cultivars, although differences among susceptibility of cultivars could be usefully considered to obtain quality productions and to reduce insecticides use both in organic and conventional olive growing. The present study was carried out at Castelvetrano (Trapani province, Sicily), in the olive germplasm collection of Ente di Sviluppo Agricolo of the Sicilian Region and Dipartimento di Colture Arboree of the University of Palermo. From 2002 to 2005, infestation levels in drupes of 18 cv, representing the most widely cultivated in Sicily was recorded. Samplings were carried out every 11-20 days, starting from the second half of August to the end of October. Moreover, from 2003 to 2005 infestation levels were correlated with size and hardness of olives, while in 2004-2005 data on olive coloration were collected at different ripening stages. Among the cultivars producing larger olives, Nocellara del Belice resulted the most susceptible to the olive fruit fly attacks, while Nocellara messinese was the less infested one. Among cultivars with medium, small-sized fruits Moresca, Vaddarica, Nasitana frutto grosso, Minuta and Bottone di gallo were the less susceptible ones. Among the tested cultivars Nocellara del Belice was the most attacked one in every year of the research. A positive correlation between infestation and olive size was found, resulting in higher infestation levels on the cultivars producing larger olives. B. oleae showed a clear preference for green drupes, instead of reddish or blackish ones. In two out of three years a negative correlation between hardness and infestation was found in September

Effectiveness of clays and copper products in the control of Bactrocera oleae (Gmelin)

Repellent and antiovipositional products in the control of Bactrocera oleae (Gmelin) find a great interest in organic farming, because of the lack of effective products able to kill the olive fruit fly larvae and eggs. This study is the continuation of a research on the effectiveness of kaolin and copper hydroxide carried out in 2003 and 2004 in Castelvetrano and Trapani (Sicily, Italy). In 2005 a product containing 95% of kaolin, Surround WP, was tested in two organic table olive orchards, Nocellara del Belice cv., in Trapani province; in the first one (located in Castelvetrano) this kaolin was compared to copper hydroxide (Coprantol Ultramicron) and rotenone (Bioroten), in the second one (located in Partanna) it was compared to a product containing 100% of bentonite (Biobenton), to a product containing copper oxychloride (Cuprobenton) and to Surround WP + copper hydroxide. In 2005, at Castelvetrano all plots gave no statistically significant differences, due to the low infestation level reached until harvesting on 8th October (total infestation in all plots 5-9%). On the other hand at Partanna, regarding the harmful infestation of the whole sampling period (11th August- 14th November), the two kinds of clays recorded statistically significant better results than the untreated plot, while the results of copper oxychloride plot were intermediate, with significant differences from kaolin plots, but without differences with bentonite and untreated theses. The oils extracted from olives of the four treated theses resulted of excellent quality (free acidity 0.1-0.2%, peroxide value 3-4), while untreated olives produced a still extra virgin oil with a higher free acidity (0.6%, peroxide value 4). In the different theses tested on this site the olive fruit fly infestation was limited to a good level for table olives until 18th, 28th September, 19th, 24th and 29th October in untreated, copper oxychloride, bentonite, kaolin and kaolin +copper hydroxide theses respectively. The tested products containing kaolin, bentonite, copper hydroxide and oxychloride are effectively able to limit B. oleae infestation to a good level for olive oil production, moreover, considering the earlier harvesting of table olives, these products, particularly the first three of them, give a new opportunity for controlling the olive fruit fly also in organic farms for table olive production

Tests on the effectiveness of kaolin and copper hydroxide in the control of Bactrocera oleae (Gmelin)

Repellent and antiovipositional products in the control of Bactrocera oleae (Gmelin) find a great interest in organic farming, because of the lack of effective products able to kill the olive fly preimmaginal stages. In 2003 in Castelvetrano (Trapani province, Sicily), tests on the effectiveness of Surround WP, a product containing 95% of kaolin, were carried out on three table olive cultivars, Nocellara del Belice, Moresca and Tonda Iblea. In 2004, in the same field and on the same cultivars, BPLK kaolin was tested too. In the second year the two products containing kaolin were also tested on Cerasuola cultivar in an organic olive grove located in Trapani, comparing them with copper hydroxide. At Castelvetrano both in 2003 and in 2004 B. oleae infestation levels of the plots treated with the two products containing kaolin were statistically lower than those of the control plots. In this site, in 2004 Surround WP protected olives significantly better than BPLK kaolin, limiting olive fly harmful infestation up to 17-23% vs. 68-87% of BPLK plots. At Trapani in 2004, the two products containing kaolin and copper hydroxide showed statistically significant differences from the untreated control, but not among themselves, limiting the harmful infestation up to 3-37% vs. 87% of the control. The different results of 2004 recorded by Surround WP and BPLK kaolin in the two olive groves seems linked to the different rainfall of the period after the last treatment, 64 mm in three rainy days at Castelvetrano and 41 mm in eight rainy days at Trapani; BPLK kaolin was probably washed away more than Surround WP. The tested products containing kaolin and copper hydroxide are effectively able to limit B. oleae infestation to a very good level for olive oil production, moreover, considering the earlier harvesting of table olives, these products give a new opportunity for controlling the olive fly also in the organic olive groves for table olive production

FIRST RECORD IN ITALY OF PSYLLAEPHAGUS BLITEUS RIEK (Hymenoptera Encyrtidae) PARASITOID OF GLYCASPIS BRIMBLECOMBEI MOORE (Hemiptera Psyllidae)

Psyllaephagus bliteus Riek (Hymenoptera Encyrtidae), parasitoid of the red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera Psyllidae), has been recorded for the first time in Italy in September 2011. The arrival of P. bliteus in Sicily is due to an accidental introduction, probably together with its host, as already happened in New Zealand, Brazil, Spain and Morocco

Strategie di controllo di Bactrocera oleae (Rossi) nell’olivicoltura biologica da olio e da tavola.

I buoni risultati ottenuti nell’olivicoltura biologica da olio sono legati alla raccolta anticipata che limita le infestazioni tardive di Bactrocera oleae (Rossi) e gli effetti negativi delle infestazioni in atto. Molto utilizzate per il controllo della mosca sono le catture massali. L’infestazione dannosa registrata nei due mesi precedenti la raccolta risulta strettamente correlata alla qualità dell’olio, mentre non lo è l’infestazione totale alla raccolta. Gli insetticidi consentiti nell’olivicoltura biologica sono molto poco utilizzati. Nelle situazioni di forte pressione della mosca soltanto i trattamenti con argille e prodotti del rame riescono a mantenere bassi i livelli d’infestazione. L’attenta gestione dell’oliveto nella produzione di olive da tavola è importante per ottenere precocemente adeguate pezzature dei frutti. Le sole punture di ovideposizione si sono dimostrate poco o per nulla visibili ad occhio nudo sulle olive trasformate e non ne compromettono l’estetica

Soglie di dannosità e strategie di controllo di Bactrocera oleae (Rossi) nell'olivicoltura biologica da tavola

Olive fly control is the main limit to the diffusion of organic table olives production, because of the lack of effective larvicides. Few studies on damages in table olives due to B. oleae and on applied damage thresholds are recorded. Results of this research show that sterile and fertile olive fly punctures are no more detectable by the naked eye on the surface of processed table olives; on the contrary exit holes are still clearly visible and affect the appearance of olives. Damage threshold applied before sizing and selection by processors of Nocellara del Belice cultivar ignores punctures and consists of 10% of 3rd instar larvae or 5% of exit holes; after sizing and selection exit holes threshold lowers to 1%. Our tests on olive fly control in organic table olive production suggest that early ripening cultivars, less susceptible cultivars, an orchard management able to reach olive size early, a low olive fly pressure (because of the year or local conditions) allow to maintain table olives below the damage threshold; one to three sprays with clays and copper products, particularly kaolin and copper hydroxide, in most cases resulted in an effective reduction of B. oleae attacks

The use of kaolin to control Ceratitis capitata in organic citrus groves.

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera Tephritidae), is the key pest in some organically managed citrus orchards in Sicily. The effectiveness of processed kaolin (Surround WP) for control of C. capitata damage was tested in field trials carried out in 2003-2004 on two early ripening citrus species: satsuma (Citrus unshiu Markow.) and clementine (Citrus clementina Hort. ex Tan.). Although the number of males captured in trimedlure baited traps was high in both years and in both orchards, the percentage of damaged fruit varied greatly from almost 0% (satsuma 2003) to more than 60% (clementine, both years). Nevertheless, the application of processed kaolin significantly reduced damage caused by C. capitata on both citrus spe- cies on preharvest fruit on some dates and on harvested fruits in both years. The kaolin was easily removed from harvested fruit by washing. Processed kaolin has potential for reducing damage caused by C. capitata in organic and conventional citrus or- chards

Role of spontaneous plants as a reservoir of alternative hosts for Semielacher petiolatus (Girault) and Citrostichus phyllocnistoides (Narayanan) (Hymenoptera, Eulophidae) in citrus groves

The role spontaneous plants could eventually play towards populations of two exotic parasitoids, Semielacher petiolatus (Girault) and Citrostichus phyllocnistoides (Narayanan), was investigated in five Sicilian citrus groves. Both species were obtained from two herbs typically living beneath the citrus trees in the period of scarce availability of P. citrella larvae on citrus plants, and precisely: S. petiolatus was reared from Cosmopterix pulcherimella Chambers, leafminer on Parietaria diffusa M. et K., while C. phyllocnistoides on the same species and on a Liriomyza species associated to Mercurialis annua L., these last two host records being new for the parasitoid. Vegetational diversity can then enhance survival and maintenance of populations of exotic parasitoids in citrus agroecosystem, providing them with alternative hosts. The incidence of parasitism of S. petiolatus and C. phyllocnistoides on non-target hosts was, however, so low (2.8% for S. petiolatus on C. pulcherimella, and 8.3% and 3.3% for C. phyllocnistoides on C. pulcherimella and Liriomyza sp. respectively) that a negative impact on both native leafminer and autochthonous parasitoid populations can be excluded