Manuel González-Núñez

Effects of processed kaolin on pests and non-target arthropods in a Spanish olive grove

The particle film technology based on processed kaolin sprays has been recently introduced for the control of the olive fruit fly Bactrocera oleae (Rossi), the key pest of olive groves. A 3-year field experiment was conducted from 2005 to 2007 at Villarejo de Salvanés, Spain to assess the efficacy of a kaolin-based product (Surround WP) for controlling B.oleae and two other olive insect pests: the olive black scale Saissetiaoleae (Olivier) and the olive psyllid Euphylluraolivina (Costa). The effects of Surround WP on the arthropod community of olive trees and on natural enemies were also evaluated. In a high olive fruit fly pressure year (2007), Surround WP sprays significantly reduced the incidence of B. oleae and that of S. oleae. However, Surround WP treatments did not have any effect on E. olivina populations. Both the abundance and the diversity of arthropods were reduced by Surround WP treatment. The principal response curve (PRC) analysis revealed a significant deleterious effect of Surround WP on the natural enemy arthropod community of the olive grove. The most affected taxa were the following: the coccinellids Scymnus mediterraneus Iablokoff-Khnzorian, Stethorus punctillum Weise and Hyperaspis reppensis (Hbst.); the mirid Brachynotocoris ferreri n. sp. Baena (in litteris); different species of Orius and the families of Philodromidae, Scelionidae, Pteromalidae, Chrysopidae and Aphelinidae. Processed kaolin is proposed as an alternative to chemical control of the olive fruit fly. However, the effect of processed kaolin treatments on natural enemies should be taken into account in a rational pest control programme.

Laboratory tests of insect growth regulators as bait sprays for the control of the olive fruit fly, Bactrocera oleae (Diptera: Tephritidae)†

BACKGROUND Insect growth regulators (IGRs) act specifically on arthropods. This selectivity makes them an interesting alternative to traditional insecticides for pest control. The aim of this work was to test the IGRs azadirachtin, cyromazine, flufenoxuron, lufenuron and pyriproxyfen as useful pesticides for the control of the olive fruit fly, Bactrocera oleae (Rossi), a key pest of olive crops. RESULTS Of the products tested, the chitin-synthesis inhibitor lufenuron showed the highest efficacy. The life parameter showing the strongest effect was the egg hatch, because lufenuron caused nearly 100% egg mortality 7 days after treatment. However, sterility was not transmitted from the treated males to the untreated females. The LC50 and LC90 values for a 7 day evaluation period were 19.3 and 86.2 µg AI mL(-1) respectively. Azadirachtin, cyromazine and flufenoxuron also caused significant increases in egg mortality. However, these increases were less than those produced by lufenuron. Pyriproxyfen had a stimulatory effect on B. oleae fecundity. CONCLUSION Applied as a bait treatment, a procedure used frequently in the field for the control of B. oleae, lufenuron is potentially useful against this important pest.

Laboratory evaluation of alternative control methods against the false tiger, Monosteira unicostata (Hemiptera: Tingidae)†

BACKGROUND Monosteira unicostata is an important pest of almond tree in the Mediterranean region requiring control methods alternative to synthetic pesticides. The efficacy of kaolin, azadirachtin and potassium salts of fatty acids combined with thyme essential oil against adults and fourth instar nymphs of this tingid was evaluated in laboratory assays. RESULTS In no choice assays with adults, kaolin significantly increased mortality compared to control (42.7% versus 23.8%) and reduced the oviposition of females (11.8 versus 35.3 eggs), the feeding activity (169.6 versus 471.2 excrements) and the damage caused (1.1 versus 2.3 damage index). In choice assays with adults, the repellence index calculated for kaolin (48.2%) was significantly higher compared to control (-15.3%), resulting in oviposition, feeding and damage deterrence indices also significantly higher than the control. In no choice assays with nymphs, all products increased mortality and reduced the feeding activity and the damage caused on leaves. Potassium soap with thyme essential oil and azadirachtin were the most effective compounds (98.0% and 97.6% mortality versus 13.3% control mortality, respectively). CONCLUSION The products tested have shown high and different efficacy on nymphs and adults of Monosteira unicostata. This activity might be suitable for the practical application of these compounds to control its populations under real field conditions.

Time course study of Bactrocera oleae (Diptera: Tephritidae) pupae predation in soil: the effect of landscape structure and soil condition

Environmentally friendly control measures are necessary for the olive fruit fly Bactrocera oleae (Rossi). Predation of pupae in soil should be better understood because it contributes to the natural control of pest populations. A time course field trial was carried out in 2015 and 2016 in 15 olive orchards selected to represent a gradient of landscape complexity. Exclusion cages were used to estimate predation rate. A combination of tillage intensity and soil coverage by herbaceous vegetation, hereafter referred to as soil condition, was also assessed as a factor affecting predation rate. The viability of the pupae recovered from the field was also evaluated. Predation was higher in the autumn than in late winter–early spring, although predation rate values were generally quite low. Landscape structure affected predation. In the autumn, the area of Mediterranean scrublands promoted predation in the olive groves. In late winter–early spring, weak tendencies were registered. Soil condition affected predation in autumn as well. The intense tillage and poor soil coverage were related to lower values of predation rate. To favour conservation biological control of B. oleae by pupae predation, it is advisable to reduce the intensity of soil management, especially in autumn, and to preserve areas of scrublands surrounding the olive groves.

Ultrastructural Morphology of Larva II of Taeniothrips inconsequens (Terebrantia: Thripidae)

Abstract Thysanoptera comprises both economically neutral species and economically important pests of crops. The immature stages of many pest species are not well known and, ironically, those are the most harmful stages for crops. Taeniothrips inconsequens (Uzel) has been reported on at least 35 different host plant species and it is found almost worldwide, but the knowledge of this species is still incomplete. Herein we present SEM images of the larva II of T. inconsequens with comments and remarks on specific features for the accurate identification of this species.

First report of bivoltinism in Isocolus (Hymenoptera, Cynipidae): Isolocus melikai Pujade-Villar n. sp. from the Iberian Peninsula

ABSTRACT A new species of the genus Isocolus Förster, 1869 (Hymenoptera, Cynipidae: Aylacini) is described. It induces galls on the capitula of Centaurea ornata Willd. (Asteraceae), an endemic of the Iberian Peninsula. Isocolus melikai Pujade-Villar n. sp. is morphologically closely related to I. freidbergi Melika, 2008, forming gall on C. verutum L., 1755, and endemic to the North West of the Arabian Peninsula. Urophora cuspidata (Meigen, 1826) (Diptera, Tephritidae) has also been obtained from similar galls on C. ornata. Isocolus melikai Pujade-Villar n. sp. was found in 16 of the 326 inflorescences (capitula) sampled, while both species (I. melikai Pujade-Villar n. sp. and U. cuspidata) were found together only in three of these capitula. The galls are also described and a probable parasitoid of Ormyrus Westwood, 1832 (Hymenoptera, Ormyridae) is mentioned. The most important characteristics to differentiate adults and galls are illustrated. Biological data are provided showing that I. melikai Pujade-Villar n. sp. is bivoltine.