Soft Scale Insects Research Articles

Predators of scale insects (Hemiptera: Coccoidea) and their role in control in Egypt.

Predators are one of the most important bioagents in natural and biological control of scale insects (Hemiptera: Coccoidae). This review includes the literatures of Egyptian scale insects predators including lists of armored scale insects, soft scale insects, mealybugs and other scale insects families predators

Common scale insects (Hemiptera:Coccoidea) in Egypt

The scale insects are small insects of the order Hemiptera, generally classified as the Superfamily Coccoidea. There are about 8,000 species of scale insects. Scale insects feed on a wide variety of plants, and scale species are considered pests. This review article is presenting the ecological aspects of some important scale insects and mealybugs infesting horticulture plants in Egypt. Armored scale insects (Hemiptera: Diaspididae) like Aulacaspis tubercularis Newstead, Pseudaulacaspis pentagona (Targioni-Tozzetti ), Parlatoria oleae (Clovee), Parlatoria ziziphi (Lucas), Fiorinia phoenicis Balachowsky and Hemiberlisia lataniae (Signoret). While, the soft scale insects (Hemiptera: Coccidae) showed by Pulvinaria tenuivalvata (Newstead), Pulvinaria psidii Mask., Saissetiacoffeae (Walker) and Ceroplastes floridensis Comstock. In case of mealybugs was represented with Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), Icerya seychellarum (Westwood) (Hemiptera: Monophelibidae) and Ferrisia virgata (Cockerell) (Hemiptera: Pseudococcidae). Family: Asterolecaniidae exampled by Asterolecanium pustulans Ckll. (Hemiptera: Asterolecaniidae).

Seasonal activity of the red-striped soft scale insect, Pulvinaria tenuivalvata (Hemiptera:Coccidae) infesting sugarcane fields at Qena, Egypt

The red-striped soft scale insect, Pulvinaria tenuivalvata (Newstead) (Hemiptera : Coccidae) is a serious pest on sugarcane. As a basic study for developing future management of this scale species, seasonal activity of different stages of this insect was carried out through two successive seasons (2006/2007 and 2007/2008) at Esna district, Qena governorate. The obtained results showed that, P. tenuivalvata had four peaks occurred in mid of July, mid-September, beginning of November and beginning of December per season. The second season of study cleared that the total population of this insect was higher in comparison to the first season of investigation, which may due to the influence of favourable factors. The combined effect of the tested weather factors was responsible about some in the total population. The percentages of explained variance (E.V.) indicate that all tested variables were together responsible for (30.6 and 42%) during the two seasons of study, respectively.

Behavioral responses to specific prey and host plant species by a generalist predatory coccinellid (Cryptolaemus montrouzieri Mulsant)

Cryptolaemus montrouzieri is a generalist coccinellid used in the biocontrol of soft scale insects and mealybugs. However, the success of biocontrol field releases is variable. In the native range of the beetle, a close geographical and temporal association between C. montrouzieri and native pseudococcids on Araucaria cunninghamii (hoop pine) has been demonstrated. We investigated the feeding and behavioral responses of C. montrouzieri to various combinations of prey and host plants. These experiments included orchard trees and the pest species against which the beetle is released as a biocontrol agent, as well as endemic plant and prey species with which it is associated in its native range. Beetle oviposition rate was reduced but not prevented by the absence of prey of a suitable life stage. In no-choice tests C. montrouzieri fed more readily on Pseudococcus sp. mealybugs, the genus with which it is most regularly associated in its native range. Olfactometer trials demonstrated that C. montrouzieri responds more quickly to the Australian native mealybug, Ps. araucariarum, than other species. In the same trials C. montrouzieri actively avoided Citrus sp. fruit. Olfactometer trials did not otherwise show a clear response to any prey or host plant combination. This is in contrast to the associations recorded in long term field observations of the beetle in its native range. We conclude that behavioral investigations of generalist predators should include the prey and plant associations that are most commonly recorded within the original distribution of the predator.

The efficiency of certain chemical and non-chemical insecticides against the mango soft scale insect, kilifia acuminata (Signoret) on mango trees in Ismailia Governorate.

Two experiments were carried out to evaluate the efficiency of chemical and nonchemical insecticides on the mango soft scale insect, kilifia acuminata (Signoret) infesting mango trees in Ismailia Governorate. The first experiment was carried out at the first of January, 2007 in El-Kantra Gharb district and the second experiment was carried out at the first of January, 2008 in El-Kantra Gharb district, Ismailia Governorate, respectively. The obtained results of the first experiment indicated that Admiral gave the highest reduction percentage (91.44%), followed by Biroanza (85.53%), Biover (84.30%) and Malathion which gave (78.82%) percentage of reduction. The least effective compound was Conserve which showed (69.47%) percentage of reduction. The obtained results of the second experiment showed that Admiral the most superior compound which gave (86.14%) percentage of reduction. The rest of compounds could be descendgly arranged as follows: Gogopa oil (81.97%), Super Royal oil (81.97%), Biover (79, 29%), Royal oil (74.35%), and Diver and oil (72.17%) percentage of reduction. The least effective insecticide was Masrona oil which gave (72.03%) percentage of reduction of the different stages of the mango soft scale insect.

Control measures of two soft scale insects (Hemiptera: Coccidae) infesting guava and mango trees in Egypt

At present the nigra scale, Parasaissetia nigra (Nietner) and the cottony camellia scale Pulvinaria floccifera (Westwood) (Hemiptera: Coccidae) are among the most important pests on guava and mango trees in Egypt. The present investigation was set up to study the effect of different compounds on P. floccifera and P. nigra on guava and mango trees, respectively. The results indicated that in the first season (2010), the treatment with different compounds (Biofly “Beauveria bassiana”, Neemazal “Azadirachta indica”, and Super Misrona oil) gave a moderate reduction of percent in the population of adult females and nymphs of P. nigra and P. floccifera respectively, as compared to Malathion and its mixture (“Super Misrona oil+Malathion”) which gave a higher reduction rate after the 1st, 2nd and 3rd weeks after spraying. Also, these compounds gave a moderate mortality to the parasitoids as compared to Malathion and its mixture (“Super Misrona oil+Malathion”) which gave higher toxicity after the 1st, 2nd and 3rd weeks after spraying. The data obtained in the second season (2011) were also similar to those obtained in the first season (2010). It can be concluded that treatment with Biofly, Neemazal and Super Misrona oil gave satisfactory control of different stages of P. nigra and P. floccifera and their parasitoids, Diversinervus elegans Silvestri, Metaphycus lounsburyi(Howard), Microterys flavus (Howard) and Coccophagus sp., Metaphycus zebratus Mercet, M. flavus , respectively, as compared to Malathion and its mixture “Super Misrona oil+Malathion”.

NEW RECORDS OF THE SOFT SCALE INSECTS HOSTS ASSOCIATED WITH THE PROMISING PARASITOID, SCUTELLISTA CAERULEA (FONSCOLOMBE) (HYMENOPTERA:PTEROMALIDAE) IN EGYPT

Scutellista caerulea (Fonscolombe) ( Hymenoptera : Pteromalidae) is one of the most promising parasitoid of soft scale insects of the world and Egypt. The present work dealt with the host range and distribution of this species in Egypt during 2005-2010. The result indicated that the recorded species was associated with 8 soft scale insect species in 9 governorates, two of them as recorded here as a new host insects for the first time in Egypt. These are Ceroplastes rusci (L.) and Coccus hesperidum L. (Hemipetra : Coccidae). An updating list of parasitoids of soft scale insects in Egypt and a key of these parasitoids were also included.

Life History of an Exotic Soft Scale InsectPhalacrococcus howertoni(Hemiptera: Coccidae) Found in Florida

We investigated the life history of an exotic soft scale insect, Phalacrococcus howertoni Hodges and Hodgson that damages croton and several other economically important ornamental and fruit plants in Florida. There was no difference in the development, survival, and reproduction of this scale insect species when reared either on croton or on buttonwood at 27 ± 1°C, 12:12 (L:D) h and 65% R. H. The scale insect practiced ovoviviparity. We observed that eggs that came out from vulva hatched to first instars immediately. Newly hatched nymphs had a tendency stay underneath the female body for somewhat less than approximately 24 h and then disperse throughout the leaf area for feeding. Females went through 3 immature stages (first, second, and third-instar) prior to becoming adults, while males had 4 immature stages (first, second, third (‘pre-pupa’), and fourth instar (‘pupa’)). Survival in the first instars was the lowest (50.0–50.9%), while the survivorship of the other instars was as follows: second instars (88.9–90.0%), third instar males (92.9–93.7%), third instar females (92.9–94.8%) and fourth-instar males (96.0–97.6%).Thus, approximately 40% of the first instars survived to adults. The pre-oviposition period was 17.6–19.1 d and the oviposition period was 13.9–15.5 d. Lifetime fertility was in the range of 382.4–394.7 live first instars per female. Intrinsic rate of increase (rm) was 0.091–0.095. The lifespan of adult males was very short (less than 1 d) at 27 ± 1°C compared to that of adult females (60.3–61.5 d).

Cissococcus Cockerell (Hemiptera: Coccoidea: Coccidae), a unique gall-inducing soft scale genus on Vitaceae from South Africa, with description of a new species

The gall-inducing genus Cissococcus Cockerell is revised to include two species. The family placement of Cissococcus has been uncertain, but characters of the first-instar nymph and adult male clearly show that Cissococcus is a soft scale insect (Coccidae) and is therefore the only member of the Coccidae known to induce a complex covering gall. All stages of the type species, C. fulleri Cockerell, are described and illustrated, plus the adult and third-instar female and first-instar nymph of a new, closely-related species, C. braini Hodgson & Millar sp. n. Both species are known only from wild vines in the southeast and C. fulleri also in the northeast of South Africa, but each induces a unique gall and each appears to be restricted to a different species of Rhoicissus (Vitaceae). The galls of each species are described and figured, and gall induction in the Coccidae is briefly discussed.

Role of pteromalid parasitoid Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae) for biological control of the soft scale insects (Hemiptera: Coccidae) in Egypt

The pteromalid parasitoid, Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae) is one of the most effective parasitoid associated with soft scale insects. This work dealt with the biological role of this parasitoid during 2009 and 2010 in Egypt. The results indicated that the parasitoid, S. caerulea was emerged from 8 species of soft scale insects. The host soft scale insects were Ceroplastes floridensis Comstock, Ceroplastes rusci (L.), Coccus hesperidum L., Kilifia acuminata (Signoret), Parasaissetia nigra (Nietner), Saissetia coffee (Walker), Saissetia oleae (Olivier) and Waxiella mimosae (Signoret) (Hemiptera: Coccidae). Population abundance studies of S. caerulea were carried out on the aforementioned soft scale insects in eight locations in Egypt, being Beni Seuf, Gharbiya, Giza, Ismailia, Marsa Matruh, Northern Coast, Qena and Sharqiya. The highest rate of parasitism attained with S. oleae was found to be 38.2 and 40.9 % during the first and second years, respectively. While average parasitism rates was 21.3 and 23.5 % during the two years under consideration, respectively. The results indicated that S. caerulea was the effective parasitoid attacking some soft scale insects in Egypt. Key worlds: Pteromalidae, Scutellista caerulea, Coccidae, soft scale insect and distribution.

Description of a new species of Toumeyella Cockerell (Hemiptera, Coccidae) from Mexico, with a taxonomic key to mexican species

A new species of soft scale insect from Mexico, Toumeyella fontanai Kondo & Pellizzari sp. nov. is des-cribed and illustrated. A taxonomic key to the species of scale insects of the genus Toumeyella Cockerell known in Mexico is provided.

Ecological aspects of Sassetia spp. ( Coccidae: Coccoidae: Hemiptera) and thier natural enemies in Egypt

In Egypt, Saissetia spp. (Coccidae: Coccoidae: Hemiptera) are the most dangerous soft scale insects infesting fruit trees. The aim of this work is to study the ecological aspects of Saissetia spp.and its natural enemies in Egypt. The result indicated that Genus Saissetia Deplanche comprises here by two species These are the soft brown scale, Saissetia coffeae (Walker) and the Mediterranean black scale, Saissetia oleae (Olvier). Genus Saissetia recorded here associated with 14 parasitoid species and 16 predator species.The seasonal abundance of S. coffeae was studied for two successive years from 2009-2010 on olivetrees in Northern Coast .The obtained results showed that, the insect population reached maximum during mid September (7728 and 8368/ 60 leaves/30 twigs) in first year and second year, respectively. Numbers by parasitoids Metaphycus lounsburyi (Howard), Microterys flavus (Howard) and Scutellista cyanea Motschulsky and a predator Scymnus syriacus Mars., reached maximum (31,9,3, and19 /60 leaves/30 twigs) during September, July, September and August, in the first year, respectively and 20,8,2 and 15 during September in the second year, respectively. The seasonal abundance of S. oleae was studied for two successive years from 2009-2010 on olivetrees in El-Arish. The obtained results showed that, the insect population reached maximum during mid of August (9729/ 60 leaves/30 twigs) in first year and mid of September (6899/ 60 leaves/30 twigs) in the second year. Numbers by the parasitoids, Metaphycus helvolus (Compere), Microterys flavus (Howard) and the predators, Coccinella undecimpunctata L. and Exochomus flavipes Thunb., reached maximum (22,5,8 and 28 /60 leaves/30 twigs) during August, August ,September and August, in the first year, respectively and 24,19,4 and 22 during September in the second year, respectively.

DNA barcoding of endoparasitoid wasps in the genus Anicetus reveals high levels of host specificity (Hymenoptera: Encyrtidae)

The genus Anicetus includes economically important biocontrol agents that are introduced for control of soft and wax scale insect agricultural pests ( Ceroplastes spp.). Understanding of host–parasitoid associations is critical to the successful outcome of their utilization in biological control projects. However, identification of these parasitoids is often difficult because of their small size and generally similar morphological features, and hence, studies on the host–parasitoid associations. Here, nucleotide sequence data were generated from the mitochondrial COI gene and the D2 region of 28S rRNA to assess genetic variation within and between species of Anicetus occurring in China. The results of this study support the use of the COI and the D2 region of 28S rRNA gene as useful markers in separating species of Anicetus, even in cases where morphological differences are subtle. On the other hand, the COI gene is also useful in recognizing species with much variation in morphology. DNA barcoding reveals high levels of host specificity of endoparasitoids wasps in the genus Anicetus. Our results indicate that each Anicetus species is adapted to a limited set of host species, or even are monospecific in their host choice.

Coccophagus scutellaris(Hymenoptera: Aphelinidae): A Highly Effective Biological Control Agent of Soft Scale Insects (Hemiptera: Coccidae) in Egypt

About 953000 individuals of the cosmopolitan parasitoid,Coccophagus scutellaris(Dalman) (Hymenoptera: Aphelinidae), were released and evaluated during 2009-2010 for the control of the following soft scale insects (Hemiptera: Coccidae) infesting the following economic crops in Egypt:Ceroplastes ruscion citrus in Beni Seuf,Ceroplastes floridensisComstock on citrus in Gharbiya,Coccus hesperidumL. on guava in Giza,Pulvinaria floccifera(Westwood) on mango in Sharqiya,Pulvinaria psidiiMaskell on mango in Ismailia,Saissetia coffeae(Walker) on olive in Marsa Matruh, andSaissetia oleae(Oliver) on olive in the Northern Coast. The population ofC. scutellarisshowed a significant correlation with the build up of the population of the soft scale insects population in all of the release sites studied. The maximum rate of parasitism of the other species of parasitoids associated with soft scale insects at the release sites decreased after the release ofC. scutellaris.

Taxonomic revision of the myrmecophilous, meliponiphilous and rhizophilous soft scale genus Cryptostigma Ferris (Hemiptera: Coccoidea: Coccidae)

The present study revises the soft scale insects of the genus Cryptostigma Ferris (Hemiptera: Coccoidea: Coccidae), which comprises a group of New World species associated with ants or bees or of hypogeal habit. It includes 17 species, of which 10 species are new to science. The study is based on the external, mostly cuticular morphology of the adult females and first-instar nymphs. Taxonomic keys based on adult females and known first-instar nymphs are provided. For each species a description or redescription is given, followed by information on its distribution, host plants, and known biological information including associated ants or bees. The new species described are Cryptostigma chacoensis sp. nov., C. gullanae sp. nov., C. jonmartini sp. nov., C. longinoi sp. nov., C. melissophilum sp. nov., C. mexicanum sp. nov., C. philwardi , sp. nov. C. rhizophilum sp. nov., C. serratum sp. nov., and C. tuberculosum sp. nov. Neolecanium urichi (Cockerell) is transferred to Cryptostigma as C. urichi (Cockerell) comb. nov., and C. quinquepori (Newstead) is synonymized with Cryptostigma urichi, comb. nov. Lectotypes are designated for Cryptostigma saundersi Laing, Lecanium silveirai Hempel, Lecanium urichi Cockerell and Akermes quinquepori Newstead. Cryptostigma inquilina (Newstead) is amended to C. inquilinum in order to match the neutral ending “stigma”. The following names are treated as nomina nuda: Cryptostigma jamaicensis and Lecanopsis jamaicensis (Ben-Dov, 1993: 97).

BIONOMICS OF THE GUAVA SOFT SCALE INSECT, PULVINARIA PSIDLI (MASKELL) (HEMIPTERA : COCCIDAE) IN EGYPT

The guava soft scale insect , Puk90aria psidii (Maskell) (Hemiptera : Cocddae) is considered one of the most important pest infesting guava in Egypt. The aim of this work is to study the survey of host plants, geographical distribution and natural enemies of the guava soft scale insect, P. psidi in Egypt as well as the biological studies of the guava soft scale, on guava, grape and mango. The obtained results indicated that the guava soft scale insect infested 8 plant species belonging to 5 genera in 5 families, distributed in 9 governorates. Eleven species of parasitoids were collected and recorded Also seven species of predators were recorded attacked P.psithi. Temperatures greatly influenced the development of P.psidii. The lowering of the temperature increased the dimension of the soft scale insect and prolonged the developmental period. The results on guava, grape and mango showed that the life cycle of P.psklii at 30°C were 67.0±0.79, 67.0±7.88 and 79.8±1.95 days, respectively. These results indicated that P.psithi preferes guava, followed by grape and mango .

New records of encyrtid (Encyrtidae: hymenoptera) parasitoids of scale insects (Coccoidea: Hemiptera) in Egypt

The family Encyrtidae is one of the largest families among the Chalcidoidea with over 3000 nominal species known throughout the world of which thirty-eight have been recorded in Egypt (Abd-Rabou, 2006). It represents the largest group of natural enemies of soft scales (Coccidae: Hemiptera) with several hundred species in 45 genera. Prinsloo (1997) provided an excellent review and key to the genera of encyrtids associated with soft scale insects. The following represents the results of a survey of encyrtid parasitoids associated with scale insects in Egypt (Hemiptera: Cocciodea) conducted in 2009.

Biology and behavior of Metaphycus angustifrons Compere (Hymenoptera: Encyrtidae), a newly discovered parasitoid of soft scale insects (Hemiptera: Coccidae) in California

Metaphycus angustifrons Compere has recently been found to be the most abundant parasitoid of brown soft scale, Coccus hesperidum L., in southern California. In laboratory experiments we examined several biological parameters of this species. M. angustifrons both oviposits and host feeds in brown soft scale and is a facultatively gregarious endoparasitoid of this soft scale insect. In contrast with other Metaphycus spp., M. angustifrons is a koinobiont parasitoid, allowing its host to grow up to 40% beyond its size at parasitism. Despite its high abundance on brown soft scale in the field, in the laboratory, high rates of parasitoid egg encapsulation are observed; about half of parasitized hosts failed to issue parasitoids. Furthermore, host scales that encapsulated parasitoids eggs showed significant reduction in development. Increased scale size at oviposition influences the size of emerging females but not the size of males. Female M. angustifrons are synovigenic. They emerge from their hosts without mature eggs and begin maturing eggs after they are provided a carbohydrate source. Carbohydrates prolong the life span of both female and male M. angustifrons. The size of female wasps influences egg load but not longevity. Finally, based on laboratory observations, M. angustifrons uses citricola scale almost exclusively for host feeding and not for oviposition. These results suggest that the role of this species in citricola scale’s decline in southern California in the 1950s–1960s was negligible.

Taxon-specific multiplex-PCR for quick, easy, and accurate identification of encyrtid and aphelinid parasitoid species attacking soft scale insects in California citrus groves

Citricola scale, Coccus pseudomagnoliarum Kuwana (Hemiptera: Coccidae), is a serious pest of citrus in California’s San Joaquin Valley, but not in southern California where a complex of Metaphycus spp. Mercet (Hymenoptera: Encyrtidae) suppress it. This has created interest in using these (and other Metaphycus) species for biological control in the San Joaquin Valley. A critical step in assessing an organism’s potential for biological control is the ability to accurately identify it. For Metaphycus spp., this currently requires slide mounted adult specimens and expert taxonomic knowledge. We present a simple, quick and accurate method to identify any life stage of the ten major parasitoids of soft scales in California citrus, based on amplification of ribosomal DNA, using the polymerase chain reaction (PCR). Three multiplex-PCR protocols amplify products of taxon-specific sizes, allowing direct diagnosis of taxa accommodated by the PCR, and reducing identification time to a fraction of that of existing methods.

Parasitoid developmental mortality in the field: patterns, causes and consequences for sex ratio and virginity

1. Sex ratio theory predicts that developmental mortality can affect sex ratio optima under Local Mate Competition and also lead to 'virgin' broods containing only females with no sibling-mating opportunities on maturity. 2. Estimates of developmental mortality and its sex ratio effects have been laboratory based, and both models and laboratory studies have treated mortality as a phenomenon without identifying its biological causes. 3. We contribute a large set of field data on Metaphycus luteolus Timberlake (Hymenoptera: Encyrtidae), an endoparasitoid of soft scale insects (Hemiptera: Coccidae), which has sex allocation conditional on host quality and female-biased brood sex ratios. Developmental mortality within broods can be both assessed and attributed to distinct causes, including encapsulation by the host and larval-larval competition. 4. Thirty per cent of M. luteolus offspring die during development with 65% of this mortality because of encapsulation and 28% because of larval competition. The distributions of mortality overall and for each cause of mortality separately were overdispersed. 5. The probability of an individual being encapsulated increased with clutch size, while the probability of being killed by a brood mate declined with increasing clutch size and with increasing per capita availability of resources. 6. The sexual compositions of broods at emergence were influenced by both the degree and the type of mortality operating. At higher levels of mortality, single sex broods were more common and sex ratios were less precise. Overall, virginity was more prevalent than predicted and was more greatly affected by the occurrence of competition than by other sources of mortality, almost certainly because competition tended to eliminate males. 7. The reproductive and developmental biology of M. luteolus appears to be influenced by a complex interplay of maternal clutch size and sex allocation strategies, offspring-offspring developmental interactions, host defence mechanisms and postemergence mating behaviour. Despite the great sophistication of sex ratio theory, it has not yet evolved to the point where it is capable of considering all of these influences simultaneously.