Coccinella Undecimpunctata Research Articles

The introduction of the eleven-spotted ladybird Coccinella undecimpunctata to New Zealand in 1874: the first use of a ladybird for biological control, or a spurious record created by cumulative misreporting?

The introduction of the eleven-spotted ladybird Coccinella undecimpunctata to New Zealand in 1874 has been widely quoted as the first importation of an insect for biological control in New Zealand and one of the first anywhere. However, searches of historical records show no evidence that such an introduction was made or attempted. Instead, there is clear evidence that the presently accepted record arose by a process of cumulative misreporting. An account of discussions in the Entomological Society of London in December 1873 about possible introductions of various beneficial insects to New Zealand was misreported by the American entomologist C. V. Riley, and several subsequent authors restated his version with further modifications and additions. This created the record of the introduction of C. undecimpunctata to New Zealand in 1874 that has been accepted and repeated ever since.

Differential Efficacies of Nomuraea Rileyi and Isaria Fumosorosea on Some Serious Pests and the Pests’ Efficient Predator Prevailing in Tomato Fields in Egypt

Abstract The efficiency of the two microbial control agents Nomuraea rileyi and Isaria fumosorosea, were evaluated against Bemisia tabaci and Myzus persicae pests in tomato cultivations The safety levels of the agents, to the predator Coccinella undecimpunctata, were also studied under laboratory and field conditions. Results showed that under laboratory conditions, LC50 values for N. rileyi and I. fumosorosea were 103.7x104 and 139.4x104 spores/ml against B. tabaci, respectively, while the corresponding values for M. persicae were 89.1x104 and 149.8x104 spores/ml, respectively. Under the field conditions, the percentages of infested plants with B. tabaci and M. persicae were significantly decreased after treatments with both fungi as compared with the corresponding controls. At the El-Esraa farm (Nobaria region), the weights of the tomato yield were 2,417 and 2,911 kg/feddan when I. fumosorosea and N. rileyi were applied respectively, as compared with 2,010 kg/feddan in the corresponding controls. The corresponding yields in El-Kassaseen were 2,699 and 2,999 kg/feddan, respectively, as compared to 1,990 kg/feddan in the control. The present study showed that C. undecimpunctata exhibit relatively high and reasonable resistance to N. rileyi and I. fumosorosea at the highest lethal concentration (1x108 spores/ml) for both tested preys.

NATURAL ENEMIES ATTACKING THE MEALY APHID, HYALOPTERUS PRUNI (GEOFFROY) IN PEACH ORCHARD AT ISMAILIA GOVERNORATE, EGYPT

The present investigation was carried out at Ismailia Governorate during 2010 and 2011 seasons to evaluate the seasonal activity of the parasitoids and predators associated with the mealy aphid Hyalopterus pruni population. During the study two parasitoid species belonging to Aphidius colemani Viereck and Aphidius picipes (Nees) and six predator species, Chrysoperla carnea Steph., Coccinella undecimpunctata L. Aphidoletes aphidimyza Rond., Syrphus corollae F. Cydonia vicinia nilotica Muls. and Scymnus interruptus Goeze. were recorded. The highest percentage of parasitism by the two parasitoids were recorded on the half of May (48.11%), during 2010, while in the second season 2011 was recorded in the last week of May (51.56%) with on average percentage of parasitism 20.77 and 18.03% during the two successive seasons respectively. Laboratory experiments were carried out to study some biological aspects of the main natural enemies associated with the mealy aphid. The obtained results indicated that the developmental period, as well as adult longevity of the parasitoid A. colemani, was affected by temperature and food. However, the developmental period decrease as temperature increase. Total developmental periods of A. colemani ranged between 9.2-37.37 days, also the longevity was affected by temperature and food for A. colemani. Studying the behavior of the same parasitoid at varying host densities showed a decrease of leaf – arrival times and host arrival times with increasing of host density but number of stings and number of mummies increased with increase of host density. Statistical analysis showed that temperature and relative humidity were significant with some insects and insignificant with the others.

Two Strains of Male-Killing Wolbachia in a Ladybird, Coccinella undecimpunctata, from a Hot Climate

Ladybirds are a hot-spot for the invasion of male-killing bacteria. These maternally inherited endosymbionts cause the death of male host embryos, to the benefit of female sibling hosts and the bacteria that they contain. Previous studies have shown that high temperatures can eradicate male-killers from ladybirds, leaving the host free from infection. Here we report the discovery of two maternally inherited sex ratio distorters in populations of a coccinellid, Coccinella undecimpunctata, from a hot lowland region of the Middle East. DNA sequence analysis indicates that the male killing is the result of infection by Wolbachia, that the trait is tetracycline sensitive, and that two distinct strains of Wolbachia co-occur within one beetle population. We discuss the implications of these findings for theories of male-killing and suggest avenues for future field-work on this system.

Role of natural enemies, climatic factors and performance genotypes on regulating pests and establishment of canola in Egypt

Screening twenty available advance lines of canola plant based on population density of the recorded pests throughout 2011 and 2012 seasons at Ismailia Agricultural Research Station Farm, Egypt was studied. The cabbage aphids; Brevicoryne brassicae , thrips; Thrips tabaci , diamondback moth; Plutella xylostella, leafminer; Liriomyza sp. , whitefly; Bemisia tabaci and two-spotted spider mite; Tetranychus urticae were surveyed pests in canola. Six predacious species related pests; Coccinella septempunctata, Coccinella undecimpunctata, Stethorus gilvifrons , Chrysoperla carnea, Syrphus corollae and Orius spp. Diaretiella rapae, Cotesia plutellae and Diadegma inslare were the most common parasitoids emerging from the collected samples. The analysis of variance revealed significant variation among dates of observations, lines and in their interaction for all surveyed pests and their natural enemies. The percentage of explained variance of abiotic factors (minimum–maximum temperatures and relative humidity) and biotic factors (predators and parasitism percentages) altogether in the population densities of B. brassica , T. tabaci , P. xylostella, Liriomyza sp. , B. tabaci and T. urticae in the second season were the greater percentage values as 87.0%, 94.7%, 88.9%, 70.1%, 63.2%, and 68.3%, respectively, compared to the first season (60.4%, 89.6%, 47.7%, 31.1%, 45.5% and 69.8% respectively). Mean performance of agronomic characters, phenotype’s coefficient of variation (PCV), genotype’s coefficient of variation (GCV), environmental coefficient of variation (ECV), heritability (Hb) and genetic advance (GS%) for yield and its attributes in canola genotypes were also studied. These results could be involved in breeding programme cultivated to improve future integrated pest management programme of canola in Egypt.

BIOLOGICAL CONTROL OF TOMATO PESTS IN EGYPT

Biological control trial on tomato plants were carried out at Mubarak City for Scientific Research and Technology Application, New Borg El-Arab, Alexandria, Egypt during two tomato summer seasons; 2008 and 2009 compared with field treated with insecticides. The most serious insect pests in both fields were Heliothis armigra, Spodoptera littoralis and S. exigua larvae. The pests control in the biological field depended mainly on releasing of the coccinellid species and the parasitoid Trichogramma evanescens. The releases were timed according to the catches of the pheromone traps and the weekly survey of the insect pests. The pests, control in the traditional field depended only on insecticide treatments. In 2008 season in the biological control field, five releases of mixture of coccinellid predators; Coccinella undecimpunctata, C. sptempunctata and Hypodimia trideampunctata at ratio of to 17: 7 : 5, respectively. In the second season, six releases of C. undecimpunctata and one of parasitoid, Trichogramma evanescens were done in biological control field. In the corresponding insecticide treatment field, four insecticide applications were carried out in the first season 2008, while in the second season, three insecticide treatments were applied. The infestation rates in the first season in tomato fruits were 1.3 and 3.8% in biological control and insecticide treated fields, respectively. While in the second season, these rates were 0.2 and 2.7% in the two fields, respectively. The tomato production was estimated with 9174 and 3867 kg/fed. in biological control and insecticides treated field in 2008 season, respectively, while in the second season those were 5804 and 3812 kg/fed., respectively.

BIOLOGICAL CONTROL OF APHIS CROCCIVORA KOCH ON PHASEOLUS VULGARIS L. PLANTS AT FAYOUM GOVERNORATE

A study was carried out to estimate population density ofcowpea aphid, Aphis craccivrora Koch and its predators associatedbean plants.Population fluctuation of A. craccivrora and its three predators,i.e., Coccinella undecimpunctata L., Chrysoperla carnea Steph andSyrphus corollae F. were studied and released on bean whichsurrounded by cabbage plants as compared with other fields unsurrounded at Sennoris district, Fayoum Governorate during summerplantation 2011/2012.The obtained results showed that the population density of threepredators at bean fields surrounding by cabbage more than twice(<100%) neighboring ones by mean counts by mean counts were101.8 and 42.3 predators /20 plants, respectively. Statistical analysisshowed highly significant differences between the tested field and theneighboring ones.The obtained results indicated that there was reduction in aphidpopulation ranged between 9.53 to 75.20 by mean 47.79% concerningthe number of the predators. Results also revealed that there werehighly significant increase in bean green yield over neighboringcheck field (control) of about 70.0 % in bean plots inter-cropped withcabbage plants .

POPULATION FLUCTUATION, BIOLOGICAL FEATURES OF DUBAS BUG (Ommatissus lybicus DeBerg (HOMOPTERA :TROPIDUCHIDAE ) ATTACKING DATE PALM TREES (Phoenix dactylifera L.) AND ITS BIOLOGICAL CONTROL BY Chrysoperla carnea (Steph.) LARVAE.

The Palm trees, attacking by many insect pests and among the most important of these insect pests Dubas bug Ommatissus lybicus DeBerg (Homoptera: Tropiduchidae ). The study of the population fluctuation of Dubas bug O. lybicus was carried out in Helwan on date palms in correlation with studying associated natural enemies. Field studies were carried out during two successive seasons (2010/2011 and 2011/2012) by fortnightly visits to examine the fronds of the selected palms. The data showed that there are two generations per every year (spring and autumn generations) on Date palm trees. There was a negative correlation between Dubas numbers and each of temperature and relative humidity. There was no significant differences between the two seasons. The most widely spread predators were Chrysoperla carnea (Steph.), Coccinella undecimpunctata L., Sphodromantis sp. As respect to biological studies on dubas bug, O. lybicus were carried out in 2009. The obtained results showed that the insect pest had two annual generations (spring and autumn generations) and the adult passed through five nymphal instars before maturity. The spring generation lasted 166.5±12.85 days, while autumn generation lasted 145±6.20 days. The nymphal stage lasted 53.5±1.87 days for the spring generation and 51.5±1.87 days for the autumn generation. Adult females lived 63±5.6 days and 91.4±13.6 days in spring and autumn generations, respectively. The respective figures for males were 33.5±6 and 76±9 days. The number of de­posited eggs ranged from 146.5±8.23 eggs/female for the spring generation to 146.5±2.45 eggs/female in autumn generation. The incubation period of the egg stage reached 117.5±1.87 days and 60±3.32days for spring and au­tumn generations, respectively. Statistical analysis showed that there were significant differences between developmental time means of eggs and adults for both generations. Results also showed that there were significant differences between spring and autumn life span periods (235.5±16.30 and 164±9.09 days, respectively). Nymphal stage of dubas bug showed five developmental instars with five moulting, with significant differences recorded among means of developmental periods among nymphal instars (8.5±1.29, 10.5±1.29, 13±1, 11.5±1.29, 14±1 and 8±1, 8.5±1.29, 12±1, 13±1, 13.5±1.29 days) for spring and autumn generations, respectively. The results showed significant differences between male and female longevities for both generations. The biological control of dubas bug by Ch.carnea Larvae, showed that the Ch. carnea larvae has the ability to consume average 16.4±6.9 nymphs of the first nymphal instar of dubas bug during 24 hours.

Bionomics of Pollinia pollini (Costa) (Hemiptera: Asterolecanidae) in Egypt

Pollinia pollini (Costa) (Hemiptera: Asterolecanidae) is considered as one of the most important pest infesting olive trees in Egypt. The aim of this work is to study the survey of host plants, geographical distribution and natural enemies as well as the dynamic of P. pollini on olive trees in Egypt. The obtained results indicated that P. pollini infested only olive trees in two Governorates. These are Alexandria and Fayoum Governorates. No parasitoid species were collected and recorded in the present work. Three species of predators were recorded that attacked P. pollini in Egypt. These are the coccinellids, Coccinella undecimpunctata L., Scymnus seriacus Mars. and the Neuroptera species, Chrysoperlla carnae Steph. Also the present study included the dynamics of P. pollini and its predators on olive trees in Alexandria Governorate during 2010 and 2011. Statistical analysis of the effect of weather factors on the population of P. pollini during the 2years under consideration was discussed. It was concluded that maximum, minimum temperatures and % relative humidity are significant on the population of P. pollini. The trend over both years indicated the occurrence of two generations per year for P. pollini on olive trees in Alexandria.

Side effects of the entomopathogenic fungus Beauveria bassiana on the predator Coccinella undecimpunctata

The effect on predators of the biopesticide based on Beauveria bassiana spores was studied. A high concentration of the pathogen showed adverse effects on the predator (Coccinella undecimpunctata) and its biological aspects: 2, 4 and 8 g/L eliminated egg deposition in treated females. Spores at 4 g/L affected significantly the longevity of adults, duration of larvae and pupal period.

ATTRACTIVENESS AND EFFECTS OF INSECTARY PLANT FLOWERS ON CERTAIN APHIDOPHAGOUS INSECTS AS BIO-AGENTS

The relative attractiveness of flowering plants to some aphidophagous species; predators (Syrphus corollae Fabricius, Chrysoperla carnea Steph., Coccinella undecimpunctata L.and Paederus alfierii Koch,and the parasitic wasp Aphidius sp. was evaluated under laboratory conditions. Flowers included: coriander (Coriandrum sativum L) chamomile , (Matricaria chamomilla, ) geranium (Pelargonium graveolens Ait ) and Fennel ( Foeniculum vulgare .Miller ) sweet basil ( Ocimum basillicum, L, ). The obtained results revealed that the tested natural enemies exhibited different degrees of selectivity in response to olfactory stimulant produced by the flowers. Chamomile flowers exhibited higher attractiveness to the hoverflies (S. corollae) than to the other tested predators .Chry carnea exposed to different flowers oduor showed the highest attractiveness to fennel followed by coriander with no significant differences. Coriander, chamomile and fennel flowers attracted the highest percentage of C. undecimpunctata adults with no significant differences. P alferii recorded the highest percentage of attractiveness towards sweet basil ( Ocimum basillicum, L, ) flowers .Choise tests illustrated that Chry. carena, S. corollae and C.undecimpunctata exhibited the lowest preferabilty to geranium and sweet basil. On the contrary. P, alferii ., showed the highest preferabilty tosweet basilflower. Flower color may influences choice. Yellow and white flowers were particularly attractive Chamomile, fennel, and sweet basil flower colors were preferred by all tested natural enemies. Choice and no choice tests recorded that the aphelinid parasitoid Aphidius sp. exhibited the highest percentage of attractiveness and prefferability to flower color of chamomileand coriander . coriander and chamomile flowers increased longevity in C. undecimpunctata. Mean longevity was 45.0 ± 8.9 days with only water, 51.0 ± 3.0 days with chamomile flowers and 58.7 ± 6.5 days when given access to coriander flowers. Parasitism percentage by the aphelinid parasitoid, Aphidius sp .adult significantly increased when fed on coriander or chamomile in comparison with control. So, Coriander and Chamomile could be a potential insectary plants for enhancing parasitoid fitness and efficacy.

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.

Natural enemies of the latania scale, Hemiberlesia lataniae (Hemiptera: Diaspididae) in Egypt

The latania scale, Hemiberlesia lataniae (Signoret) (Hemiptera: Diaspididae) is a dangerous pest in different locations in Egypt. During the present work, 17 species of natural enemies were collected from samples of H. latania. These are: Aphytis aonidiae (Mercet), Aphytis chilensis Howard, Aphytis lingnanensis Comepre, Aphytis mytilaspidis (Le Baron) (Hymenoptera: Aphelinidae), Chilocorus bipustulatus L. (Coleoptera: Coccinellidae), Chrysoperlla carnae Steph. (Neuroptera: Chrysopidae), Coccinella undecimpunctata L (Coleoptera: Coccinellidae), Encarsia aurantii (Howard), Encarsia lounsburyi (Berlese and Paoli) (Hymenoptera: Aphelinidae), Exochomus flavipes Thunb. (Coleoptera: Coccinellidae) and Habrolepis aspidioti Compere and Annecke (Hymenoptera: Encyrtidae), Marietta leopardina Motschulsky (Hymenoptera: Aphelinidae), Orius laevigatus Fieb. (Hemiptera: Anthocoridae), Pharoscymnus various Kirsch., Rodalia cardinals Muls (Coleoptera: Coccinellidae), Scymnus syriacus Mars. (Coleoptera: Coccinellidae) and Syrphus corollae Fabricius (Diptera: Syrphidae). Abundance of the latania scale, H. lataniae natural enemies were evaluated in different locations in Egypt, representing various bioclimatic regions during two successive years 2009-2010. The results indicated that the parasitoid, H.aspidioti the most abundant species associated with H. lataniae infested mango trees in Giza. The maximum rate of parasitism reached 9.1 and 7.3% in October, 2009 and 2010, respectively. The percentage of parasitism ranged from 0.1 to 9.1% in the first year and from 0.3 to 7.3% in the second year. The predator C. carnae was the most abundant species and occurred all over the years under investigation on H. lataniae on olive trees in Alexandria and the maximum number was 25 individuals /60 leaves and 15 twigs in July in the first year and 17 individuals/60 leaves and 15 twigs in June in the second year. Keys for parasitoids and predators associated with the latania scale, H. lataniae are included.

Populations of predators and parasitoids of Bemisia tabaci (Hemiptera: Aleyrodidae) after the application of eight biorational insecticides in vegetable crops

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is an important pest of vegetables and many other crops worldwide. Eight biorational insecticides (based on oil, plant derivatives, insect growth regulator and fungus) were evaluated in the field for their influence on populations of six natural enemies of B. tabaci. Natural populations of two predators [Chrysoperla carnea Stephen (Neuroptera: Chrysopidae) and Orius spp. (Hemiptera: Anthocoridae)] and two genera of parasitoids [Encarsia spp. and Eretmocerus spp. (Hymenoptera: Aphelinidae)] were evaluated in eggplant (Solanum melongena L.). Also, augmented field populations of three predators [C. carnea, Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) and Macrolophus caliginosus (Wagner) (Hemiptera: Miridae)] were evaluated in cabbage (Brassica oleracea var. capitata L.), cucumber (Cucumis sativus L.) and squash (Cucurbita pepo L.). Regardless of natural enemy or crop, jojoba oil, Biovar and Neemix had the least effect on abundance of the natural enemies in comparison with the other insecticides during a 14 day evaluation period. Conversely, Admiral, KZ oil, Mesrona oil, Mesrona oil + sulfur and natural oil had a high detrimental effect on abundance of the natural enemies. These results demonstrate the differential effects of biorational insecticides for whitefly control on predators and parasitoids in the field.

The influence of some honeybee products as a diet substitute on the different stages of Coccinella undecimpunctata L. in Egypt

Several natural diets of honeybee products were tested for rearing Coccinella undecimpunctata L. under laboratory conditions. Two groups of tested adult and larval insect have been fed on the tested diets, the first group were fed on the tested honey bee products diets without adding aphids, while the second group fed on the same honeybee products with aphids added. The oviposition period in the first group was significantly shorter than control. The tested diets supplied with royal jelly + aphid and/or pollen grains + aphid caused the longest oviposition period. Diets of aphid alone and bee honey with aphid recorded the shortest oviposition period. Fecundity of ladybird was the highest in the tested diets with aphids than diets without aphid and/or aphid diet alone. The durations of larval and pupal stages were significantly different when compared with the diets with or without aphid and/or aphid diet alone. Further results indicated that the diets of royal jelly caused the shortest duration in larval and pupal stages.

Prevailing insects in Roselle plants, Hibiscus sabdariffa L., and their efficiency on pollination

Field surveys of Roselle plant fields were conducted during two successive seasons of 2006 and 2007. The total counted insects on Roselle, Hibiscus sabdariffa attained 16 species belong to seven insect Orders [(Hemiptera (3 species), Homoptera (1 species), Lepidoptera (3 species), Neuroptera (1 species), Coleoptera (3 species), Diptera (1 species), Hymenoptera (4 species)]. Variable numbers of insects were counted on different Roselle varieties and in the two seasons. The most prevailing insect species were the piercing sucking pests [Empoasca spp.; Spilostethus longulus Dallas; Nezara viridula L. and Oxycarenus hyalinipennis (Costa)] and the predators [Polistes sp., Coccinella undecimpunctata and Scymnus syriacus]. Honeybee (Apis mellifera L.) proved to be the most abundant pollinator, averaging 13, 17, 18 individuals/25double strikes in cultivations of Sudani, Masri and White varieties of Roselle plants during flowering of the first season respectively. Similar results were also obtained in the second season. The highest number of honeybees was recorded around 10 am to midday during the flowering stage for the two seasons. It was obvious that the effects of the two hydrothermal, factors temperature and relative humidity, had slight or negligible effects on the occurrence of insect pollination throughout the two seasons of the study, while statistical analysis of the obtained results showed that the productivity of Roselle plant (mean number of seeds and mean weights of seeds) were significantly affected by pollinators.

Inundative field releases and evaluation of three predators for Bemisia tabaci (Hemiptera: Aleyrodidae) management in three vegetable crops

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator (Coccinella undecimpunctata L. [Coleoptera: Coccinellidae]), a common green lacewing predator (Chrysoperla carnea Stephen [Neuroptera: Chrysopidae]), and a mirid predator (Macrolophus caliginosus[Wagner][Hemiptera: Miridae]) were independently made in three vegetable crops (cabbage [Brassica oleracea var. capitata L.], cucumber [Cucumis sativus L.], and squash [Cucurbita pepo L.]) for the management of the sweetpotato whitefly. Approximately 1 million to 2.5 million larvae or nymphs of each predator were released in the vegetable crops during 20 weeks. Whitefly populations were reduced by ≈ 25%–45% during most of the season in each crop where each predator was released. The effect of each predator was similar on whitefly population reduction. Late in the season (October) when whitefly populations were low, generally no benefit was obtained from releasing the predators. Numbers of predators recovered during sampling in all crops were greatest for C. carnea, but this corresponded with the fact that more individuals of this predator were released than any other predator in the experiment. These results help define the utility of these natural enemies for managing B. tabaci in vegetable crops.

Synergy between chemical and biological control in the IPM of currant-lettuce aphid (Nasonovia ribisnigri) in Canterbury, New Zealand

Field trials were conducted at four Canterbury, New Zealand locations in 2005-06 to determine if the synergistic effects of biological control by natural enemies and standard drenching techniques controlled lettuce aphid populations throughout the entire growing season. Chemical usage significantly lowered aphid densities in the outer, wrapper and heart leaves compared to control plants at most times. However, in mid-summer, natural enemies, such as the brown lacewing (Micromus tasmaniae), 11-spotted ladybird beetle (Coccinella undecimpunctata) and small hoverfly larvae (Melanostoma fasciatum), were more than sufficient to control lettuce aphids without the use of insecticides. Drenching, in addition to natural enemy attack, appears to be required in early spring and late summer to maintain very low levels of lettuce aphid. Given the potential for imidacloprid resistance to develop, it may be advisable to restrict drenches to these key periods in order to allow populations of natural enemies to maintain control of prey populations. We recommend industry support the validation of action thresholds across different regions within New Zealand and focus on the seasonal biology of predators to assist growers with the sustainable long-term control of lettuce aphids. The inclusion of additional data into an economic model to compare pest damage with predator loading would be useful for growers in managing aphid problems. These results will assist in the continued improvement and development of a sustainable IPM strategy for lettuce aphids in New Zealand and elsewhere.

Effect of weed borders on insect pests and their associated predators on sugar beet and cotton plant fields

The study of the relationship between the important insect pests and their related predators on weeds border of the sugar beet and cotton fields was car ried out at Kafr ElSheikh region during two successive seasons, 2005/2006 and 2006/2007. Seven insect species, four insect pests and three predators were recorded o n both weeds border and sugar beet plants, while eleven insect species occurred on cotton p lants, seven insect pests and four predators. The most dominant predators were Scymnus spp., Coccinella undecimpunctata and Paederus alfierii. Significant correlation was found between Scymnus spp. on weeds and jassids on sugar beet and cotton. There was significant correlation between Scymnus spp. on weeds and on cotton plants (r = 0.502). Signficant correlation was recorded between Scymnus spp. on weeds and aphids on sugar beet (r = 0.598). On cotton plants, 97% of Scymnus spp. were larvae, while 100% of Scymnus spp. on weeds border were adults. There were relationship between the C. undecimpunctata and P. alfierii predators and Oxycarenus hyalinipennispest on weeds border (0.791) and on cotton plants (0.522*). Highly significant correlation was recorded between O. hyalinipennis on weeds border and the on cotton plants (r=0.676**) in the second season. The weeds border served as dwelling of the predators especially in winter. Scymnus spp. was common predators on Bermod grass (Cynodon dactylon). When the predator numbers began to decrease on weeds border began to increase on plant crops by third week of May.

Predation by Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) on Myzuspersicae Sulzer (Homoptera: Aphididae): Effect of prey density

To enhance a strategy for the biological control of Myzus persicae Sulzer (Homoptera: Aphididae) using Coccinella undecimpunctata L. (Coleoptera: Coccinellidae), it is important to understand predator–prey interactions. Hence, the voracity and functional response of 4th instar larvae and adults (males and females) of C. undecimpunctata L. on Myzus persicae Sulzer were evaluated under laboratory conditions. This study took place in small plastic boxes at varying aphid densities. Satiation was attained when 130 aphids were provided to 4th instar larvae and 90 to adult males or females. Coccinella undecimpunctata exhibited a type II functional response; fourth instar larvae displayed a lower handling time than adults and attack rates were similar between larvae and adults and, between females and males (i.e., not sex-dependent). Coccinella undecimpunctata showed to be an effective predator for the biological control of M. persicae under controlled conditions, and it is hypothesized that the presence of both 4th instar larvae and adults of this ladybird beetle could increase the efficiency on field pest suppression.