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Background: Biofumigation with defatted seed meal of Brassicaceae in the form of pellets has several advantages over the incorporation of fresh Brassicaceae crops to control soil-borne diseases. Two field experiments were established to evaluate the effect of biofumigation with brassica pellets on the survival and infectivity of Phytophthora nicotianae Breda de Haan inoculum introduced before treatments. In the spring experiment the incorporation of additional Brassicaceae cover crop (Brassica nigra L. and Sinapis alba L.) was tested, and in the summer experiment two brassica pellet doses were applied., Results: Biofumigation with brassica pellets in spring (3000 kg ha(-1) with and without plastic) or in summer (3000 kg ha(-1) with or without plastic; 6000 kg ha(-1) without plastic) had no significant effect on the survival of P. nicotianae, regardless of the incorporation of additional Brassicaceae cover crop in spring. Reduction in infectivity in spring was related to the application of plastic, especially when combined with brassica pellets and Brassicaceae crop. In summer, soil temperature was the main factor in the inactivation of the inoculum, especially when plastic was applied, and no additional inactivation was achieved with brassica pellets., Conclusion: In spring and summer, biofumigation with brassica pellets had no effect on the survival of P. nicotianae. Application of plastic in spring may reduce infectivity. Soil temperature is the main factor in the inactivation of inoculum in summer, especially when plastic is applied. © 2015 Society of Chemical Industry., (© 2015 Society of Chemical Industry.)

Sensitivity to mefenoxam, fresh Brassicaceae tissues, and Brassica pellets was evaluated in several isolates of Phytophthora nicotianae recovered from pepper and tomato plants. The isolates of P. nicotianae studied were classified as sensitive to mefenoxam, showing great variability among isolates in the 50 and 90% effective concentrations (EC 50 and EC 90 , respectively). Sensitivity differentiated isolates from the two hosts of origin, being isolates from tomato plants more resistant to fungicide than those from pepper plants. This differentiation also occurred in the case of fresh Brassicaceae tissues assay. The most effective biofumigant in inhibiting mycelial growth of P. nicotianae isolates was Brassica nigra. The effectiveness of B. carinata, Sinapis alba, and B. oleracea varied depending on the dose. Isolates differed in susceptibility to compounds released by the Brassica pellets and then in the EC 50 and EC 90 . No significant difference was found between the isolates depending on the host of origin. Greenhouse tests demonstrated the effectiveness of treatments with mefenoxam and with Brassica pellets to control P. nicotianae in pepper plants. Mefenoxam application could be a solution to the disease caused by P. nicotianae in tomato and pepper crops in this region but its use could increase resistance in populations. Biofumigation is a promising technique which can be further developed to form part of integrated pest management strategies.

Tobacco (Nicotiana tabaccum L.) is among the most important crops in La Vera Region (Cáceres, west-central Spain) where, since 2001, flue-cured tobacco plants showing typical symptoms of a vascular disease associated to the cyst nematode (Globodera tabacum) complex have been frequently observed (2). Symptoms observed were wilting, yellowing, and drying of the leaves, usually on one side of the plant; stunted and distorted leaves with curved midribs due to the unequal growth; and brown vascular discoloration of stems and midribs. Several diseased plants were collected during the summers of 2003 and 2004, and F. oxysporum was consistently isolated from sections of necrotic midribs. To confirm the pathogenicity of F. oxysporum isolates, plants of flue-cured tobacco (cv. Ct-681) were inoculated. Since Fusarium wilt of tobacco may be caused by F. oxysporum f. sp. vasinfectum or F. oxysporum f. sp. batatas (1), plants of cotton (cv. Acala) and sweet potato (cvs. Nemagold and Nancy Hall) were also inoculated to determine the forma specialis designation. Twenty plants per cultivar and isolate were inoculated with six isolates at the two to four true-leaf stage by pouring into the substrate 200 ml of a conidial suspension (1 × 10 5 CFU/ml). After inoculation, plants were incubated in a growth chamber at 28°C (day) and 24°C (night) with a 16-h photoperiod. All six F. oxysporum isolates were pathogenic to tobacco and sweet potato, but there were differences among isolates in time from inoculation to appearance of first disease symptoms (7 to 15 days after inoculation in tobacco and sweet potato) and also in disease severity 30 days after inoculation (60 to 100% wilt or mortality in tobacco and 50 to 100% in sweet potato). F. oxysporum was reisolated from stems of inoculated plants. No disease symptom was observed in cotton plants 60 days after inoculation, and F. oxysporum was not reisolated from them. Results of inoculation on the differential hosts indicated that disease symptoms in tobacco were caused by F. oxysporum f. sp. batatas. To our knowledge, this is the first report of F. oxysporum f. sp. batatas causing disease in flue-cured tobacco in Spain. References: (1) G. M. Armstrong and J. K. Armstrong. Phytopathology 58:1242, 1968. (2) G. Espárrago and I. Blanco. Plant Dis. 86:1402, 2002.

Virgin females of Lobesia botrana Denis & Schiffermüller were mated at ages of 1, 3, 5, 8, 12 and 16 days and the effect of mating delay on reproductive output assessed. Delayed mating did not affect female mating success but fertilization was reduced in 16-day-old females. Increased mating delays substantially affected daily oviposition pattern and resulted in a significant reduction of both fecundity and fertility, so that mean number of viable eggs laid decreased from 150 to 22 in 1- and 16-day-old mated females, respectively. Heavier females were more constrained than lighter ones by mating delays and female reproductive efficiency (no. viable eggs/female body weight) was also significantly reduced. Female longevity significantly increased and oviposition period gradually declined with mating delay. The number of viable eggs was positively correlated with both female weight and oviposition period; female longevity and female weight were also significantly correlated. However, the significance of these correlations declined with increased mating delay. Results overall indicated that mating delay drastically reduces female L. botrana reproductive output. The implications of delayed mating of females are discussed from an ecological perspective in relation to L. botrana control using mating disruption.

The genetic basis as well as the mode of inheritance of polyandry in Spodoptera exigua Hübner was studied in the laboratory by using a simple divergent selection experiment followed by F1 reciprocal crosses, F2 and backcrosses. There was an effective response to artificial selection for high (H line) and low (L line) female mating frequency with significant separation of the lines by the second generation of selection. The mean female mating frequency in the parental generation (1.57 matings per female) reached plateaus of 2.50 and 1.25 matings per female in the H and L lines, respectively, after six generations of selection. Selection response becomes saturated at about 90% and 25% levels of polyandry (percentage females re-mating) in the H and L lines, respectively, and consequently mono- and polyandric pure strains were not obtained. Polyandry levels in offspring from the H and L lines and their hybrids in F1, F2 and backcrosses consistently indicate that female mating frequency was more or less proportional to the relative amounts of genes derived from the H and L lines. Such a clear pattern of hybrid responses, together with the gradual selective changes under artificial selection, suggests the involvement of a polygenic system. Female mating frequencies from progeny of the two reciprocal F1 crosses were not significantly different, which suggest that the trait was autosomally inherited. Moreover, female mating frequency of F1 (pooled) progeny was not significantly different from the mid-parental value, which suggest no dominance. The computation of the Cavalli's joint scaling test consistently confirmed these results yielding values of d = 0.51 +/- 0.10 and h = 0.12 +/- 0.21. The broad sense heritability estimate was H2 = 0.73. It is concluded that polyandry in S. exigua is a polygenic, autosomal heritable trait and that additive genetic variance is available for selection for female mating frequency. The implications of the genetic basis of polyandry are briefly discussed in the context of current theories about this crucial insect mating system.