Vine Mealybug Planococcus Ficus Research Articles

Toxicity of Pesticides Applied in European Vineyards on Anagyrus vladimiri and Trichogramma evanescens, Parasitoids of Planococcus ficus and Lobesia botrana.

Risk assessments of chemical pesticides toward natural enemies are crucial for ensuring sustainable grapevine-integrated pest management. In this context, laboratory experiments were conducted to evaluate the toxicity of four insecticides (lambda-cyhalothrin, flupyradifurone, acetamiprid, and cyantraniliprole) and one fungicide (spiroxamine) commonly applied in German (European) vineyards on the pupae and adults of both Anagyrus vladimiri, a parasitoid of the vine mealybug Planococcus ficus, and Trichogramma evanescens, a parasitoid of the European grapevine moth, Lobesia botrana. The tested pesticides did not significantly affect the development of the pupal stage inside mealybug mummies or the emergence of the parasitoid A. vladimiri. The pesticides flupyradifurone, acetamiprid, and spiroxamine resulted in the highest mortality percentages for all emerged A. vladimiri parasitoids at 8 and 10 days after treatment compared with either in lambda-cyhalothrin or cyantraniliprole. However, all pesticides, except the diamide insecticide cyantraniliprole, significantly affected the development of the pupal stage and the emergence of the parasitoid T. evanescens. The percentages of T. evanescens emergence following the application of the fungicide spiroxamine or either lambda-cyhalothrin or flupyradifurone were significantly higher than those observed in the acetamiprid treatment. Regarding direct contact toxicity, the highest percentages (100%) of A. vladimiri adult parasitoid mortality were obtained in the flupyradifurone, acetamiprid, and spiroxamine treatments, while the lowest mortality percentages were observed in lambda-cyhalothrin, cyantraniliprole, and untreated control treatments. According to the IOBC classes of toxicity, flupyradifurone, acetamiprid, and spiroxamine were classified as harmful, while both lambda-cyhalothrin and cyantraniliprole were classified as slightly harmful to A. vladimiri adults. As such, all pesticides had a significant impact on the survival of exposed T. evanescens adults. The highest percentages of adult T. evanescens mortality were obtained in the flupyradifurone, acetamiprid, and spiroxamine treatments, with the fungicide spiroxamine resulting in significantly higher mortality percentages than either flupyradifurone or acetamiprid, while the lowest mortality percentages were found in the lambda-cyhalothrin and cyantraniliprole treatments. Therefore, applying the insecticides acetamiprid and/or flupyradifurone and the fungicide spiroxamine should be avoided when A. vladimiri and/or T. evanescens are naturally present or released in grapes. The insights gained from these two easy-to-rear parasitoid species allow analogous conclusions to be drawn for closely related species in vineyards belonging to either family Encyrtidae or Trichogrammatidae, which are not easy to rear. Interestingly, using the safer insecticides lambda-cyhalothrin and/or cyantraniliprole could be compatible with both parasitoid species, which could be sustainably exploited in either conservation or augmentative biological control in vineyards.

Host stage preference and demographic parameters of Leptomastix dactylopii (Hymenoptera: Encyrtidae) on vine mealybug Planococcus ficus (Hemiptera: Pseudococcidae)

BackgroundThis study was conducted to investigate host stage preference and demographic parameters of the parasitoid species, Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), the parasitoid of vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), an important pest in vineyards in many countries.ResultsThe results revealed that L. dactylopii was not able to develop on the 1st and 2nd nymphal instars of P. ficus and preferred female mealybugs as the host to the 3rd nymphal instar. Hind tibia length and head capsule width of both female and male parasitoids emerged from the mummies of mealybugs parasitized in the female stage were greater than the values of the parasitoids emerged from the mummies of mealybugs parasitized in the 3rd nymphal instar. Demographic parameters of the parasitoid were calculated with the use of development and reproduction data obtained from life table of L. dactylopii. The intrinsic rate of increase was determined as (r = 0.1527 d−1), finite rate of increase as (λ = 1.1650 d−1), net reproductive rate as (R0 = 46.0667 offspring), and mean generation time as (T0 = 25.0830 d).ConclusionsIt was concluded that L. dactylopii was able to develop, especially in the female and in the 3rd nymphal instar of P. ficus and could be used for biological control of the vine mealybug.

EFFECT OF Planococcus ficus (SIGNORET) ON THE GROWTH OF THREE WINE GRAPE CULTIVARS

Damage caused by herbivores reduces plant survival and growth through its effects on mechanisms involved in tolerance to herbivory. Infestation by sap-sucking insects negatively affects the expression of metabolites related to photosynthesis and growth traits, which in an agricultural context can be useful for designing pest management and crop breeding programs. The effect of infestation by the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) on chlorophyll content and plant growth in three varieties of Vitis vinifera L. (Garnacha, Tempranillo and Nebbiolo) was evaluated. A common garden experiment was conducted with 60 plants of each variety and two P. ficus infestation treatments (infested and non-infested). Plant height, number of leaves, leaf area and chlorophyll content index were measured before and after P. ficus infestation for each plant and, additionally, the relative change rate (RCR) for each trait was estimated. The infestation reduced theRCR of the number of leaves (22.57 %) and leaf area (41.65 %). The effect of infestation on plant growth changed between varieties. Nebbiolo plants with infestation showed a reduction of RCR in plant height compared to non- infested plants (57.32 %), while Garnacha and Tempranillo varieties showed similar values in both treatments. A negative effect of P. ficus infestation on plant height, number of leaves and leaf area was found. Results suggest that the Nebbiolo variety is less tolerant to P. ficus attack. Farmers should adopt more rigorous monitoring and control measures when growing this variety.

Elevated CO2 Levels Impact Fitness Traits of Vine Mealybug Planococcus ficus Signoret, but Not Its Parasitoid Leptomastix dactylopii Howard

Carbon dioxide (CO2) is one of the primary factors driving climate change impacts on plants, pests, and natural enemies. The present study reports the effects of different atmospheric CO2 concentrations on the vine mealybug Planococcus ficus (Signoret) and its parasitoid wasp Leptomastix dactylopii (Howard). We investigated the life-history parameters of both species on grapevine Vitis vinifera (L.) plants grown under elevated (eCO2) and ambient (aCO2) CO2 levels in a greenhouse and in a vineyard free-air carbon dioxide enrichment (FACE) facility. The greenhouse experiments with an eCO2 level of around 800 ppm showed a significant increase in survival rates, a strong trend towards declining body size, and an increasing fecundity of female mealybugs, while fertility and development time did not change. However, none of these parameters were altered by different CO2 concentrations in the VineyardFACE facility (eCO2 level around 450 ppm). On the other hand, the parasitism success, development time and sex ratio of L. dactylopii, reared on P. ficus under eCO2 or aCO2, varied neither in the greenhouse nor in the FACE facility. These results suggest that future CO2 levels might cause small-scale changes in vine mealybug fitness; however, this is not necessarily reflected by parasitoid performance.

Vine and citrus mealybug pest control based on synthetic chemicals. A review

Synthetic chemicals are extensively used to limit the substantial crop damage induced by two closely related scale insects, the vine mealybug Planococcus ficus (Signoret) and the citrus mealybug Planococcus citri Risso (Hemiptera: Pseudococcidae). Both organisms are economically important pests occurring in vineyards and/or in citrus orchards worldwide. Synthetic chemicals can be either incorporated in pesticides aimed at directly controlling these pests or used as semiochemicals (i.e., sex pheromones) for monitoring, mass trapping, mating disruption, and/or for kairomonal attraction to enhance parasitoid performances. Growing evidence of both an alarming bee decline and destruction of auxiliary fauna driven by pesticides have stimulated an urgent need for in-depth research clarifying the adverse side effects of pesticides on beneficial arthropods. We have reviewed the current knowledge on mealybug pest control based on insecticides and semiochemicals. We highlight the following major advances: (1) How the active substances of insecticides (four organophosphates, imidacloprid, buprofezin, and spirotetramat) affect target and non-target organisms, (2) in which contexts and how a semiochemical-based strategy could be applied to deal with serious mealybug infestations, and (3) the implications of the appropriate exploitation of these synthetic chemicals for sustainable development. Using selective insecticides with novel modes of action and long-lasting efficacy in combination with eco-friendly semiochemical-based tools is a promising strategy for developing sustainable integrated pest management programs. This would help to maintain biodiversity dynamics and vital ecosystem services, thereby sustaining crop yields.

Assessment of the performance of some new insecticides for the control of the vine mealybug Planococcus ficus in a Tunisian vineyard

Mealybugs (Hemiptera: Pseudococcidae) cause major economic losses in many Tunisian grapegrowing areas. In an attempt to improve management strategies for the Vine Mealybug (VM) Planococcus ficus (Signoret), three insecticides, imidacloprid, Prev-Am® and spirotetramat, were evaluated for their effect on this insect on vine, with reference to methidathion. The systemic insecticide spirotetramat (Movento® 150 OD) provided the greatest control performance of the VM populations, compared to the contact insecticide methidathion, the systemic insecticide imidacloprid applied through furrow irrigated system, and to Prev-Am®, a new contact biopesticide. Three weeks after treatment, VM eggs and adult females were missing from spirotetramat-treated vines. Additionally, spirotetramat supplied a long-residual activity against VM populations and prevented further spread of these insects on vine leaves. Therefore, this new systemic insecticide could be incorporated in an Integrated Pest Management program for VM control in Tunisian vineyards. Despite its short-residual activity, Prev-Am® was shown to be more effective than both methidathion and imidacloprid, mainly on VM eggs and L3 nymphs, and resulted in the highest level of VM L1-L2 nymph decrease on vine trunks. Hence, this biopesticide might prove useful for VM management in vineyards. 

Comparative development and reproduction of Planococcus ficus and Planococcus citri (Hemiptera: Pseudococcidae) on grapevine under field conditions

Abstract Mealybugs are major pests in grape‐growing areas worldwide, causing direct and indirect crop damage. The vine mealybug Planococcus ficus (Signoret) is a key pest in most of grape‐producing countries, whereas the citrus mealybug Planococcus citri (Risso) is reported as being destructive in Brazilian and Spanish vineyards. We examined the adaptation of the citrus mealybug to grapevine by investigating its development, reproduction and life‐history parameters under Mediterranean field conditions in comparison with those of P. ficus. Both mealybug species developed and reproduced successfully on grapevine. However, P. ficus showed a shorter development time, larger female body size, and higher fecundity, fertility and survival than P. citri. The life‐history parameters further highlighted the different growth potential of vine and citrus mealybug populations because P. ficus exhibited a net reproductive rate and an intrinsic rate of increase two‐ to four‐fold higher than that of P. citri. Furthermore, the vine mealybug population doubled its number in approximately half time with respect to the citrus mealybug. Overall, the results of the present study show a better development and reproductive performance and a higher population growth potential of P. ficus compared with P. citri, indicating a higher capacity of the vine mealybug to develop on grapevine in Mediterranean vineyards.

Occurrence and Transmission of Grapevine Virus A in South African grapevines

Antiserum prepared to a local isolate of grapevine virus A (GVA) was used in immunosorbent electron microscopy (ISEM) with decoration and in an unlabelled antibody enzyme-linked immunosorbent assay (ELISA) for the screening of grapevine sources for the presence of virus. GV A occurred extensively in grapevine plantings showing visual symp· toms of leafroll or indexing positive for leafroll. GV A was found not to be associated with either stem pitting or fleck symptoms. It occurred mostly in association with undecorated closterovirus (CV)-like particles. Limited ISEM with decoration of the CV-like particles using antiserum to a Swiss isolate of CV 2 200 nm, (CV type I) confirmed the presence of a second CV in local grapevine sources. In addition, it indicated the presence of a third CV -like particle longer than GVA. GVA together with undecorated CV-like particles were also detected in initially GVA-free LN-33 grapevines growing under field conditions and naturally infected with Ieafroll. GV A and CV type I were also present in the vine mealybug Planococcus ficus, following exposure to a grapevine source carrying these viruses. H'lwever, due to lack of CV type I antiserum, only GV A was confirmed in grapevine following controlled transmissions with P. ficus although undecorated CV -like particles were present. The reliability of the ELISA detection procedure appears to be influenced by seasonal fluctuations in GV A concentrations.

Endophytic Beauveria bassiana in grapevine Vitis vinifera (L.) reduces infestation with piercing-sucking insects

Fungi are important natural pathogens of arthropod pests and are successfully used as biocontrol agents in various crops. In addition to colonizing arthropods, evidence has accumulated that some entomopathogenic fungi like Beauveria bassiana can endophytically colonize a wide array of plant species. However, only limited information is currently available on the endophytic colonization of grapevines with B. bassiana and whether the fungus still maintains its pathogenic habit against insect pests.Greenhouse and field experiments were conducted to optimize endophytic establishment of the entomopathogenic fungus B. bassiana in younger, potted plants and mature grapevine plants in the vineyard. We used two different commercialized B. bassiana strains, applied either as conidial suspensions (ATCC 74040 and GHA) or as a formulated product (Naturalis®, strain ATCC 74040) on grapevine leaves. The potential of endophytic B. bassiana to provide protection against putative target pest insects like the vine mealybug Planococcus ficus was assessed in a bioassay using surface sterilized leaves. Endophytic survival of B. bassiana inside leaf tissues of seven-week-old potted plants was evident for at least 21days after inoculation, irrespective of the inoculum used. Endophytic B. bassiana reduces infestation rate and growth of P. ficus. In the vineyard B. bassiana was detected as an endophyte in mature grapevine plants up to five weeks after last application with significant reduction of infestation with grape leafhopper, Empoasca vitis.

The Vine Mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) Damaging Vineyards in Brazil.

In the last decade, the incidence of mealybugs (Hemiptera: Pseudococcidae) in vineyards has increased, especially on crops grown under plastic covering, in the Serra Gaúcha region of southern Brazil where the major Brazilian wineries are concentrated. Eggs, nymphs, and female adults were collected in two highly infested vineyards in Bento Gonçalves City, Rio Grande do Sul, Brazil. Mealybugs were identified by morphological and molecular techniques as the vine mealybug Planococcus ficus (Signoret). This is a principal mealybug pest of vineyards worldwide, and this is the first record of damage from this species in Brazil.

The Sublethal Effects of a Systemic Insecticide on the Vine Mealybug Parasitoids Anagyrus sp. near pseudococci (Girault) and Coccidoxenoides perminutus (Timberlake) (Hymenoptera: Encyrtidae)

Imidacloprid is a systemic insecticide used for the control of the vine mealybug Planococcus ficus. However, biological control of P. ficus is the primary alternate management method recommended for the integrated control of this pest. We therefore aimed to establish the detrimental effects on the development of Anagyrus. sp. near pseudococci and Coccidoxenoides perminutus feeding on imidacloprid-contaminated vine mealybugs as indicated by the subsequent emergence and survival of the F1 generation. The results imply that A. sp. near pseudococci and C. perminutus were equally susceptible to imidacloprid, based on probit analysis. However, survival was significantly different between the control and insecticide treatment for C. perminutus (χ2 = 23.80; d.f. = 3; p < 0.001), but not for A. sp. near pseudococci (χ2 = 5.07; d.f. = 3; p = 0.17). As this study was laboratory based, the effect of imidacloprid on populations of parasitoids in the field should be assessed further. Treatment recommendations to minimise the impact on parasitoids are discussed briefly.

Interspecific competition between Anagyrus pseudococci and Leptomastix dactylopii, parasitoids of the vine mealybug Planococcus ficus

Interspecific competition among parasitoids plays a key role in the population dynamics of insect pests and may affect the outcome of biological control programs. The aim of this study was to examine competition between two parasitoids, Anagyrus pseudococci (Girault) and Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), of the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) under laboratory conditions. The mealybug was parasitized by both parasitoid species at the same time (within 2 h) or sequentially at 24, 48 or 72 h intervals. When mealybug were parasitized at the same time by both parasitoids, the emergence rate from the host was 68.63 % for L. dactylopii and 31.37 % for A. pseudococci. The emergence rate of females was higher than that for males, but the duration of development of males was shorter than for females in both species. When A. pseudococci had parasitism priority for 24 h, there was no difference between the emergence rates of both parasitoids. When A. pseudococci had parasitism priority for 48 and 72 h, the emergence rates of A. pseudococi were 65 and 77.50 % respectively. Also, the duration of development of A. pseudococci was shorter than that of L. dactylopii for all three time intervals. When L. dactylopii had parasitism priority for 24 and 48 h, there was no difference between the emergence rates of both parasitoids. However, when L. dactylopii had parasitism priority for 72 h, the emergence rate of L. dactylopii was 94.83 %. Only when L. dactylopii had parasitism priority for 48 h, there was a difference between both parasitoids and the duration of development of A. pseudococci was shorter than for L. dactylopii. Consequently, it was found that competition may occur between L. dactylopii and A. pseudococci if they are used together to control P. ficus. Also, it was determined that the A. pseudococci population may be more affected than the L. dactylopii population by this competition.

First insights into grapevine transcriptional responses as a result of vine mealybug Planococcus ficus feeding

Plant response to insect feeding appears to be highly specific with regard to the organisms in the system. Here, we report on the interaction between grapevine Vitis vinifera L. plants and a phloem-feeding insect pest, the vine mealybug Planococcus ficus (Homoptera: Pseudococcidae). Plants were exposed to P. ficus for periods of 6 and 96 h, respectively, after which they were analysed for differences in gene expression levels using microarrays. Grapevine displayed a fairly low response to mealybug feeding, with only 107 and 149 transcripts being differentially expressed compared to uninfested control plants after 6 and 96 h of mealybug feeding, respectively. Most of these genes are known to be expressed by grapevine or other plants as a response to microbial pathogen attack. In addition, intermediate exposure times (24, 48 and 72 h) of grapevine plants to P. ficus feeding were investigated using qPCR analysis of ten genes associated with known plant defence responses. Results showed that only a single gene, pathogenesis-related protein 1, was differentially expressed after 48 h of mealybug feeding compared to control plants. Therefore, our study has shown that on a transcriptional level grapevine plants respond weakly to attack by vine mealybugs, which is analogous to a range of other studies on plant responses to piercing-sucking insects.

Evidence for gene flow between two sympatric mealybug species (Insecta; Coccoidea; Pseudococcidae).

Occurrence of inter-species hybrids in natural populations might be evidence of gene flow between species. In the present study we found evidence of gene flow between two sympatric, genetically related scale insect species – the citrus mealybug Planococcus citri (Risso) and the vine mealybug Planococcus ficus (Signoret). These species can be distinguished by morphological, behavioral, and molecular traits. We employed the sex pheromones of the two respective species to study their different patterns of male attraction. We also used nuclear ITS2 (internal transcribed spacer 2) and mitochondrial COI (Cytochrome c oxidase sub unit 1) DNA sequences to characterize populations of the two species, in order to demonstrate the outcome of a possible gene flow between feral populations of the two species. Our results showed attraction to P. ficus pheromones of all tested populations of P. citri males but not vice versa. Furthermore, ITS2 sequences revealed the presence of ‘hybrid females’ among P. citri populations but not among those of P. ficus. ‘hybrid females’ from P. citri populations identified as P. citri females according to COI sequences. We offer two hypotheses for these results. 1) The occurrence of phenotypic and genotypic traits of P. ficus in P. citri populations may be attributed to both ancient and contemporary gene flow between their populations; and 2) we cannot rule out that an ancient sympatric speciation by which P. ficus emerged from P. citri might have led to the present situation of shared traits between these species. In light of these findings we also discuss the origin of the studied species and the importance of the pherotype phenomenon as a tool with which to study genetic relationships between congener scale insects.

Life table and some feeding features of Nephus kreissli fed on Planococcus ficus

In this study certain biological and prey consumption features of the predator of mealybug, namely Nephus kreissli Fursch & Uygun (Coleoptera: Coccinellidae), fed on vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were determined under the laboratory conditions. Experiments were performed in the acclimatized room under 28 ± 1°C, 60 ± 10% r.h. and a photoperiod of 16:8 h(L:D) conditions. To determine the biological features of the coccinellid, predator individuals were continuously observed from egg stage to end of adult stage. The development, survival and fecundity of N. kreissli were determined and all the measured data were recorded daily. The total development time from egg to the eclosion of adult stage was determined as 31.6 ± 0.4 days. The lifespan of males and females was 66.0 ± 3.8 and 65.8 ± 3.5 days, respectively; and a single female laid 122.6 eggs. The raw data related to life history were analyzed by using the age-stage, two-sex life table. The intrinsic rate of increase, the net reproductive rate, and the mean generation time were 0.0709 ± 0.0036 d−1, 53.1 ± 9.5 offspring and 55.8 ± 1.3 days, respectively. The first and second instars of N. kreissli preferred egg stages of P. ficus to other stages of mealybug. On the other hand, third and fourth instars and adult predators preferred the second and third instar nymphs and adult females of the prey. It was determined that the egg consumption of N. kreissli increased with the development of larval stages, and that the highest consumption was recorded in its fourth instar.

Evaluating side effects of newer insecticides on the vine mealybug parasitoid Anagyrus sp. near pseudococci, with implications for integrated pest management in vineyards

Control of the invasive vine mealybug Planococcus ficus (Signoret) can be achieved through integration of different management strategies such as the application of chemical treatments and biological control. However, compatibility between these control methods is considered crucial when adopting integrated pest management (IPM) programs against this insect pest. The recently used insecticides Prev-Am®, a contact biopesticide, and spirotetramat, a systemic tetramic acid insecticide, were assessed in laboratory conditions for their side effects on the vine mealybug parasitoid Anagyrus sp. near pseudococci with reference to chlorpyriphos-methyl, an organophosphate insecticide conventionally used for mealybug control in vineyards. Regarding contact toxicity, chlorpyriphos-methyl caused 100% parasitoid mortality 24 h after treatment, but parasitoid mortality from Prev-Am® or spirotetramat was almost absent. Neither the total parasitoid offspring/female nor the sex ratio of the progeny was negatively affected by Prev-Am® or spirotetramat relative to the untreated control. According to the IOBC classification for laboratory trials, both Prev-Am® and spirotetramat were rated harmless (IOBC category 1), whereas chlorpyriphos-methyl was categorized as harmful (IOBC category 4) to A. sp. near pseudococci. None of the insecticides adversely affected the development of the parasitoid pupal stage inside mealybug mummies or the survival of the emerged parasitoids. The practical implications of the results for implementing mealybug IPM programs in vineyards are emphasized and discussed.

Preference of foraging ants (Hymenoptera: Formicidae) for bait toxicants in South African vineyards

Argentine ants Linepithema humile (Mayr), common pugnacious ants Anoplolepis custodiens (F. Smith) and cocktail ants Crematogaster peringueyi Emery are the main indirect ant pests in South African vineyards. These ants form mutualistic relationships with the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), an economic phloem-feeding pest of vines that excretes honeydew. Ants feed on the honeydew from mealybugs and also affect predator–prey interactions by protecting them from attack by natural enemies. This consequently reduces the efficacy of predators and parasitic Hymenoptera in controlling P. ficus. Current strategies for ant control are limited to the application of long term residual insecticides that are detrimental to the environment, labour intensive to apply and potentially disruptive to biological control. Here, we report on the development of an alternative method of ant control using baits which are likely to show delayed toxicity to these ant species. Field bait preference assessments were carried out during spring, summer and autumn in three vineyards of the Cape Winelands region, Republic of South Africa during 2007/08. Preference/non-preference is the first behaviour an ant exhibits when encountering bait and this was measured in terms of numbers of ants at bait stations. Five toxicants comprising Gourmet ant bait (containing 0.5% boric acid as active ingredient and a honeydew mimic as an attractant), boric acid (0.5%), fipronil (0.0001%), fenoxycarb (0.5%) and spinosad (0.01%) all dissolved in 25% sucrose solution were tested against a 25% sucrose solution control. Gourmet ant bait was overall the most preferred bait during spring, summer and autumn, and on some occasions being significantly more preferable to ants than the control solution.

Interference of ants (Hymenoptera: Formicidae) with biological control of the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae)

Anagyrus sp. and Coccidoxenoides perminutus are well known parasitoids used for the biological control of the vine mealybug Planococcus ficus, a key pest in vineyards. In South Africa, three ant species, Anoplolepis steingroeveri, Crematogaster peringueyi and Linepithema humile form a trophobiotic relationship with the vine mealybug in vineyards and promote the latter’s infestations to unacceptable levels. In a manipulative laboratory experiment, ants and parasitoids were allowed to forage on vine mealybug-infested butternuts and numbers were recorded for a 1 min period at 10 min intervals for 2 h. Parasitoid mortality and the number of parasitized vine mealybug females were then recorded in the presence and absence of the three ant species. Data were analyzed using a repeated measures generalized linear model (GEEs). The mean number of ants and parasitoids on the mealybug-infested butternuts differed significantly between ant species and time intervals ( p < 0.0001 in all cases). Crematogaster peringueyi and L. humile caused significantly higher mortality of both parasitoids than A. steingroeveri during the 24-h exposure period ( p < 0.0001). Coccidoxenoides perminutus parasitized significantly more vine mealybugs than Anagyrus sp. for all treatments ( p < 0.0001). Ants should therefore be controlled prior to release of parasitoids to suppress populations of ant-tended Hemiptera in vineyards.

Feeding behavior ofCryptolaemus montrouzieri on mealybugs parasitized byAnagyrus pseudococci

The citrus mealybugPlanococcus citri (Risso) and the vine mealybugPlanococcus ficus (Signoret) (Hemiptera: Pseudococcidae) are two worldwide polyphagous pests of citrus, vineyards and ornamental plants in greenhouses. Biological control of these pests may rely on the combined release of parasites and predators, which can be affected by intraguild predation (IGP). This study investigated the feeding behavior of different stages ofCryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) on mealybugs parasitized byAnagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae) 2, 4, 6, 8 and 10 days. The study was conducted in a climate-controlled room at 28±1° C, 16L:8D, and 65±10% r.h. The highest consumption values for all stages ofC. montrouzieri occurred with 2- and 4-day parasitized mealybugs, whereas the predator did not feed on either species of mealybug parasitized for longer periods, due to the onset of mummification.

Sex pheromone of the vine mealybug, Planococcus ficus in Israel: occurrence of a second component in a mass-reared population.

Two pheromonal components were detected in airborne collections from the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) mass-reared on potato sprouts. The compounds were identified as (S)-lavandulyl senecioate (I) and (S)-lavandulyl isovalerate (II) by GC and GC-MS by comparison with synthetic standards. Chiral GC analysis on a cyclodextrin column established their chirality. Compound I was identified recently as the sex pheromone of P. ficus in California. The attraction of vine mealybug males to both components I and II was demonstrated in a Petri dish bioassay and in a flight assay in the rearing chamber. Indoors, both compounds displayed a similar level of attractiveness to the mass-reared males. However, trials in a vineyard indicated that feral males were attracted only to compound I. Reanalysis of the airborne pheromone indicated that laboratory first generation daughters of females that were collected in the vineyard produce only (S)-lavandulyl senecioate (I). The relative amount of (S)-lavandulyl isovalerate (II) increased gradually in each subsequent generation of P. ficus reared on potatoes. These findings indicate that feral P. ficus mealybugs produce and respond only to (S)-lavandulyl senecioate (I), whereas mealybugs that were reared in the laboratory on potato sprouts produce and respond to both (S)-lavandulyl senecioate (I) and (S)-lavandulyl isovalerate (II).