The Response of Leaf Miner Liriomyza trifolii to Cowpea Vigna spp Plant

This study was conducted in a field located at Department of Biology/College of Sciences/University of Baghdad, from the period between the Mid of August to the second half of October 2015, in order to study the population density of cowpea leaf miner on California Ramshorn cowpea and local varieties (Bayader) and their natural enemies. The result showed fluctuation of the population density for Liriomyza trifolii on the American variety. Two peaks for population density were shown and the second was higher than the first. The highest population density was 6.5 leaf miner/ leaf while the lowest was 0.7 leaf miner/leaf at the beginning of sampling. For the local variety, three peaks were recorded. The first was the highest with 2.61leaf miner/leaf and the lowest was 0.2 leaf miner/leaf. Population density of insect was higher on American variety has higherthan the local variety in its protein content which reached to 24.3%. Two hymenopteran parasites Pediobius matallicus and Diglyphus isaaea belong to the family Eulophidae were recorded on L. trifolii. This study, the first was conducted on the leaf miner on this host plant.

Effect of Dormant Oil Treatments on White Peach Scale (Homoptera: Diaspididae) and its Overwintering Parasite Complex

The effect of dormant oil treatments on the overwintering parasite complex of white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti) was evaluated in a peach orchard in the southern coastal plain of North Carolina in 1988 and 1989. Oil treatments resulted in significant reductions in the emergence of adult hymenopteran parasites in both years. However, mortality was not complete, and a sufficient number of parasites survived to repopulate the orchard in spring.

The Seasonal History of the White Peach Scale (Homoptera: Diaspididae) and its Hymenopteran Natural Enemies in North Carolina

Hymenopteran parasites (adults) and mobile stages (crawlers, adult males) of white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti), were monitored biweekly (1986) or weekly (1987) in a peach orchard from April to December. The scale exhibited three peaks of crawler emergence, and a partial fourth generation was observed in both years. Three species of hymenopteran parasites consistently collected from traps were the primary parasites Encarsia berlesi (Howard) and Aphytis proclia (Walker), and the hyperparasite Marietta carnesi (Howard). Populations of all three parasites showed seasonal peaks of activity that differed in the two years of this study. Winter samples taken in 1985, and from 1987 through 1989 indicated differences between years in the ratio of parasites to hyperparasites overwintering.

EXPLOITING COLD-HARDINESS TO SEPARATE PISSODES STROBI (PECK) (COLEOPTERA: CURCULIONIDAE) FROM ASSOCIATED INSECTS IN LEADERS OF PICEA SITCHENSIS (BONG.) CARR.

The cold-hardiness of Pissodes strobi (Peck) and of its insect associates in leaders of Picea sitchensis (Bong.) Carr. was tested to determine whether the insect associates could be retrieved free of P. strobi for use in biological control attempts on P. strobi. Leaders were stored at −8, −16, or −26°C for periods from 1 to 14 days. All P. strobi were dead after 14 days at −16°C, whereas their dipteran predator, Lonchaea corticis Taylor, and hymenopteran parasites, Eurytoma pissodis Girault and Rhopalicus pulchripennis (Crawford), continued development after storage at −26°C. The scarcer Dolichomitus terebrans (Ratzeburg) (Ichneumonidae) survived similarly although we did not always find it in our samples; and the equally scarce Bracon pini (Muesebeck) (Braconidae) seemed susceptible to −26°C but continued development at −16°C. Of the few Allodorus crassigaster (Provancher) (Braconidae) obtained one adult emerged after 7 days at −16°C. These results show that in leader clipping operations now used for attempted control of P. strobi, most of the insect associates could be retrieved from the leaders after suitable cold treatment. Additional tests showed that cold-treated leaders could be stored outdoors in temperatures at least down to −20°C with little effect on adult emergence of insect associates. The field testing also showed that few P. strobi in leaders of P. sitchensis can survive overnight temperatures near −20°C.

PRIMARY HYMENOPTEROUS PARASITES OF NANTUCKET PINE TIP MOTH, RHYACIONIA FRUSTRANA (COMSTOCK)1

Nantucket pine tip moth (NPTM), Rhyacionia frustrana (Comstock), is a pest of several members of the genus Pinus, including commercial and ornamental species. A rather large parasitoid complex is associated with NPTM, but collecting and rearing techniques have not clearly defined the true or primary parasites attacking the NPTM. Incorrect associations may have been assumed. This report defines known primary hymenopteran parasites attacking NPTM including records for Arkansas.

BIOLOGY AND LEAF-MINING BEHAVIOUR OF PHYTOMYZA LANATI (DIPTERA: AGROMYZIDAE)

The first signs of Phytomyza lanati Spencer activity are the feeding marks of the adult on the lower leaf surface of Heracleum lanatum Michx. In Alameda County, Calif., the adults were first seen in January and the larvae were present from mid-February to mid-June. Eggs are laid in the spongy mesophyll and the serpentine mine, made by the solitary larva, is mainly confined to the palisade layer. The larva remains within a single mine until just before puparium formation. At this time the mature larva exits from the leaf through a cut in the lower surface and drops to the soil. At 75 ± 1°F the average duration of the three immature stages are 47, 36, and 60 hours. Because the depth of the mine is constant, the surface area of the mine indicates the relative volume of food consumed. A comparison of the instars shows that the amount and rate of tunnelling increases greatly with each succeeding moult. Under constant temperature there is no significant difference between the amount mined during equivalent light and dark periods.Adult activity, such as feeding, mating, and oviposition, occurs on the underside of the leaf. Feeding on the plant exudate appears necessary for sustaining adult life.Three hymenopteran parasites were reared from P. lanati.Biological characteristics served to differentiate P. lanati from other Phytomyza species.