The susceptibility of larvae of Thaumetopoea solitaria Freyer (Lepidoptera; Notodontidae, Thaumetopoeinae), fed on treated pistachio foliage, to three commercial control products derived from Bacillus thuringiensis (Bt) , was evaluated in the laboratory. Both Dipel DF and Delfin WG were highly effective against 1 st and 2 nd instar larvae at relatively low concentrations (LC 50 : 0.01–0.04%), whereas mortality of the 3 rd instar larvae reached 50% only at a Dipel DF concentration of 0.2%. The third formulation, Foray 48B, was significantly less toxic toward all tested larval instars. The susceptibility of T. solitaria to Br decreased progressively between molts, and then increased steeply during the first days following each molt. Use of the film-forming polymer Nu-Film as a wetting agent and spreader-sticker for the commercial formulation of Dipel DF improved Bt adhesion to extremely hydrophobic young Pistacia foliage, and significantly increased Bt persistence under ambient conditions. Addition of Nu-Film improved the leaf surface coverage and extended the duration of rainproofing.

The susceptibility of Thaumetopoea wilkinsoni larvae to Bacillus thuringiensis (Bt) formulations was screened in 2003 and 2004. Eggs and larvae were collected from pine forests in 11 geographical locations in Israel. Larval mortality bioassays were conducted with commercial formulations (Delfin WG, Dipel DF and Foray 48B) at concentrations ranging from 0.001% to 0.1%. Significant differences in susceptibility to Bt were recorded among populations that were treated with Bt intensively, frequently, or never. The mortality recorded in a population that was never treated with Bt was twice that in an intensively Bt-treated population. The correlation between susceptibility to Bt and the possible resistance to the microbe is discussed.

Four parasitoids emerged from leaves galled by the waspOphelimus maskelli (Ashmead) that were collected in Wagga Wagga, NSW, Australia:Closterocerus chameleon (Girault) and an unidentified Tetrastichinae species (Eulophidae); andStethynium ophelimi Huber andStethynium breviovipositor (Huber (Mymaridae).C. chamaeleon andS. ophelimi were released in eucalyptus plantations infested withO. maskelli in Israel. The recovery of the parasitoids, as well as several aspects of their possible role in control of the galls, were studied. In view of the parasitism of the galler in Wagga Wagga, we suggest that the proportion ofS. ophelimi in the Israeli population ofO. maskelli will increase markedly as soon as the gall wasp population density reaches a very low level.

Ophelimus maskelli (Ashmead) (Hymenoptera: Eulophidae), an invasive species in the Mediterranean area that occurs naturally onEucalyptus camaldulensis at Wagga Wagga in New South Wales, was studied in Israel on the same host plant. The most distinctive characteristic ofO. maskelli as compared with other congeners is the presence of only a single seta on the submarginal vein.O. maskelli shows a clear tendency to oviposit in developed, immature leaves, and it prefers to oviposit on an area of the leaf blade near the petiole. The female lays an average of 109 eggs when maintained on water alone. The egglaying distribution tended towards aggregation, and the same tendency has also been observed within and among trees. The wasp prefers to attack the lower canopy. The gall diameter ranged from 1.2 to 0.9 mm, and gall density from 11.5 to 36.0 galls cm−2, respectively. The typical color of the gall appeared as soon as third instar larva developed. Galls on shaded leaves remained green or greenish-yellow, whereas those that were exposed to the sun were reddish.O. maskelli produces three generations per year in Israel. High flight occurs among the spring generations, starting in early March. The wasps were attracted to green sticky plates much more than to the other tested colors. Heavy galling byO. maskelli results in premature shedding of the leaves, soon after the emergence of the wasps. Among the 84 eucalyptus species tested, the following 14 species were found to be suitable hosts:E. botryoides, E. bridgesiana, E. camaldulensis, E. cinerea, E. globulus, E. gunii, E. nicholii, E. pulverulenta, E. robusta, E. rudis, E. saligna, E. tereticornis andE. viminalis. This study focused on morphological and development characters that can clearly distinguishO. maskelli fromOphelimus eucalypti Gahan, and on examining the effect of crossing between eucalyptus species on the development possibilities of the wasps. Also considered were the effect of the food on adult survival, the competition between the eulophid gall makerLeptocybe invasa Fisher & LaSalle andO. maskelli, the heavy damage inflicted on eucalyptus, and the health problems and nuisance to people caused by the wasp near heavily infested trees during the mass emergence of adults.

Information on persistence ofBacillus thuringiensis (Bt) is needed to improve the microbial pest management programs against the pine processionary mothThaumetopoea wilkinsoni in pine forests in Israel. The persistence of the microbe under natural conditions of rain and sunlight was evaluated and is documented here for the first time. Pine saplings were sprayed with three commercialBt products, Foray 48B, Delfin WG and Dipel DF, all used at 32,000 IU mg−1 in a formulation with 1% (w/v) of condensed milk. In experiments conducted in November and December of 2004, the saplings were either exposed to rain and sunlight or were sheltered to avoid these environmental factors. The lowest rainfall recorded in the 8-day experiments was 16.5 mm (test 2) and the heaviest was 71.1 mm (test 1). Solar irradiation ranged from 9.4 to 10.9 MJ m−2. The minimum temperature was close to 10°C and the maximum was less than 23°C. Needles of the treated saplings and their controls were sampled after 0, 1, 5 and 8 days, and were fed to 1 st or 2 nd instar larvae. Dipel DF persisted better than Delfin WG and still retained its initial activity of 80–100% mortality on day 8 at low rainfall (test 2). Dripping ofBt from upper to lower branches was quantified with the larval bioassays. The milk formulation proved to be an effective rain-fasting adjuvant.

Mortality of Pinus halepensis seedlings was investigated in Israel during the first years of natural regeneration after fire, with special emphasis on the role of Matsucoccus josephi, drought and competition. The investigations were conducted in the native natural forest on Mt. Carmel, and in a plantation severely damaged by the scale insect at Horeshim in Samaria. M josephi was the dominant mortality agent during the first five years after regeneration, killing almost 73 % and 54% of the seedlings at Mt. Carmel and Horeshim, respectively. Neither injury nor mortality due to the scale insect was recorded during the first year after regeneration, but subsequently mortality occurred during the third and the fourth years. About 23% of the seedlings died due to drought, interspecific and intraspecific competition. Mortality due to other biotic agents, i.e., Hylastes linearis and Pityophthorus pubescens was practically nil. It is shown that resistance of regenerating population of native P. halepensis on Mt. Carmel to the scale did not differ significantly from that of regeneration of a planted Aleppo pine forest of unknown seed sources at Horeshim, despite differences in the level of injury to the adult trees on each site. Five years after natural seeding seedling density in scale-infested plots is high enough to ensure stand development. This second growth possibly displays lower susceptibility to M. josephi than the present adult population.

Mortality of Pinns halepensis was investigated in Israel during the first years of natural regeneration after fire, with special emphasis on Matsucoccus josephi and on drought and competition. The investigations were conducted in a natural forest on Mt. Carmel, erroneously believed to be resistant to the scale, and in a plantation severely damaged by the scale at Horeshim in Samaria. Matsucoccus josephi was the dominant mortality agent, killing about 47% of the seedlings during the first four years after regeneration. Neither injury nor mortality due to the scale insect was recorded during the first year after regeneration, with maximum mortality occurring during the third and the fourth years. About 23% of the seedlings died due to drought and to interspecific and intraspecific competition; most of the mortality occurred during the first two years after regeneration. Mortality due to other arthropods was practically nil. It was shown that resistance to the scale of a regenerating population of P. halepensis on Mt. Carmel did not differ significantly from that at Horeshim, despite differences in the level of injury to the adult trees at each site. Seedling density in scale-infested plots, four years after natural seeding, is high enough to ensure stands development with the second growth possibly displaying less susceptibility to M. josephi than the present adult trees.

Information is presented on new occurrences of two homopteran pests,Matsucoccus josephi Bodenheimer et Harpaz (Matsucoccidae) andPineus pini (Macquart) (Adelgidae), in Israel, Jordan and southern Lebanon.M. josephi occurs in Israel in almost all natural relicts of Aleppo pine (Pinus halepensis). It infests all plantations of Aleppo pine, brutia pine (Pinus brutia ssp.brutia) and Eldar pine (P. brutia ssp.eldarica) north of 31°12′ lat. N. Heavy damage has been observed in the Judean Foothills, Judean Mts. and northern Samaria.M. josephi and its specific predator,Elatophilus hebraicus Pericart (Hemiptera: Anthocoridae), are recorded for the first time in Jordan and southern Lebanon. The scale was found in all visited Aleppo pine and brutia pine stands in Jordan and in natural and planted brutia pine in southeastern Lebanon. Damage byM. josephi in Jordan was observed only in young plantations of Aleppo pine; in Lebanon no signs of injury were recorded.P. pini was found for the first time in Jordan, where it causes severe damage to young stands of Aleppo pine and stone pine (Pinus pinea).