Diversity, distribution and phenology of Lygus species (Hemiptera: Miridae) in relation to vegetable greenhouses in the lower Fraser Valley, British Columbia, and southwestern Ontario

Lygus spp. were collected from near and inside vegetable greenhouses during three years in the lower Fraser Valley, British Columbia (BC) and in Leamington, Ontario (ON). In BC, the dominant species was Lygus shulli, followed in abundance by L. elisus and L. hesperus; L. lineolaris was not collected in the lower Fraser Valley. In ON, only L. lineolaris was collected. In BC, L. shulli was generally distributed throughout the region, whereas L. hesperus was captured in sweep net samples only in coastal areas. Lygus hesperus appeared to be univoltine in BC. All other species in ON and BC were apparently bivoltine. In ON, numbers of adults collected outside of greenhouses correlated with numbers collected inside greenhouses whereas this was not the case in BC. Differences in flight behaviour, abundance and greenhouse construction may account for this latter difference. Our results highlight the need for different approaches to IPM of pest Lygus species in the ON and BC greenhouse industries

Effect of kaolin clay on migrant alate aphids (Hemiptera: Aphididae) in blueberry fields in the context of Blueberry scorch virus

The efficacy of kaolin clay (Surround® WP) in reducing the number of migrant aphids on blueberry, Vaccinium corymbosum L. (Ericaceae) and the incidence of Blueberry scorch virus (BlScV) was determined. Two applications of kaolin clay reduced the number of alatae collected on treated ‘Berkeley’ plants by as much as a factor of eight between 4 June and 16 August. However, five of 100 test plants located near infected fields and exposed only to migrant alatae between 10 May and 16 August became infected with BlScV: three controls and two treated with kaolin clay. The work demonstrates the importance of migrant alatae in the spread of BlScV; 5% transmission is consistent with previous estimates of annual virus spread by winged and non-winged aphids. Three of the plants became infected between 10 and 27 May (one control and two treated with kaolin clay), indicating the importance of aphid flights in May for virus transmission. Rainfall removed much of the kaolin clay and this may have affected its efficacy. The aphid data demonstrated that migrant alatae are able to discriminate between untreated and kaolin—treated blueberry plants, and that Ericaphis fimbriata (Richards), which utilizes blueberry as a host, discriminates better than other migrant species. Water trap data do not necessarily reflect the total migrant aphid composition found on plants in the field. Plant growth was not affected by the kaolin clay, but the fruit had clay residues amongst the bracts of the calyx limiting the use of this product on producing fields to the period before fruit set. Kaolin clay may be best suited to protection of nursery stock, but further work is needed to improve efficacy during wet weather and determine optimal application frequency.Note: Use of trade names or trademarks does not imply endorsement of the companies or products named nor criticism of similar ones not named

DNA barcoding and a precise morphological comparison revealed a cryptic species in the Nippolachnus piri complex (Hemiptera: Aphididae: Lachninae)

Nippolachnus is a small Palaearctic-Oriental genus of very characteristic aphids that live on the leaves of woody Rosaceae. One species, N. piri, has hitherto been regarded to be widely distributed and relatively polyphagous. Members of this genus are considered to be easy to recognize due to the absence of the ocular tubercle and triommatidia on the head. We conducted research on the morphology and generic characters of Nippolachnus piri complex using scanning electron microscopy (for the first time) and DNA barcoding. We analyzed N. piri populations on Pyrus and other plants (Eriobotrya, Rhaphiolepis and Sorbus) in Japan and the Republic of Korea. Specifically, a high genetic divergence value was found between the N. piri populations associated with different host plants. SEM investigation of the head capsule revealed that a triommatidium is present under the compound eye, despite their lack of an ocular tubercle. We propose Nippolachnus micromeli Shinji, 1924 stat. nov. as a cryptic species in the N. piri complex based on a morphological comparison, DNA barcoding and different host-plant associations. Illustrations and descriptions of studied species are given. Morphological keys to the apterae and alatae of all known species of the genus Nippolachnus are also provided

Macroevolutionary Patterns in the Aphidini Aphids (Hemiptera: Aphididae): Diversification, Host Association, and Biogeographic Origins

, the most diverse genus in the family. We used a combined dataset of one nuclear and four mitochondrial DNA regions. A molecular dating approach, calibrated with fossil records, was used to estimate divergence times of these taxa.Most generic divergences in Aphidini occurred in the Middle Tertiary, and species-level divergences occurred between the Middle and Late Tertiary. The ancestral state of host use for Aphidini was equivocal with respect to three states: monoecy on trees, heteroecy, and monoecy on grasses. The ancestral state of Rhopalosiphina likely included both heteroecy and monoecy, whereas that of Aphidina was most likely monoecy. The divergence times of aphid lineages at the generic or subgeneric levels are close to those of their primary hosts. The species-level divergences in aphids are consistent with the diversification of the secondary hosts, as a few examples suggest. The biogeographic origin of Aphidini as a whole was equivocal, but the major lineages within Aphidina likely separated into Nearctic, Western Palearctic, and Eastern Palearctic regions.Most generic divergences in Aphidini occurred in the Middle Tertiary when primary hosts, mainly in the Rosaceae, were diverging, whereas species-level divergences were contemporaneous with diversification of the secondary hosts such as Poaceae in the Middle to Late Tertiary. Our results suggest that evolution of host alternation within Aphidini may have occurred during the Middle Tertiary (Oligocene) when the secondary hosts emerged

Geographic distribution, host preferences and molecular diversity within the genus Pentalonia (Hemiptera: Aphididae)

Foottit, R. G., Maw, H. E. L. (2019): Geographic distribution, host preferences and molecular diversity within the genus Pentalonia (Hemiptera: Aphididae). Zootaxa 4701 (4): 383-391, DOI: https://doi.org/10.11646/zootaxa.4701.4.

FIGURE 3 in Geographic distribution, host preferences and molecular diversity within the genus Pentalonia (Hemiptera: Aphididae)

FIGURE 3. Histogram of length (in mm) of distal rostral segment of Pentalonia specimens classified by host group.Published as part of Foottit, R. G. & Maw, H. E. L., 2019, Geographic distribution, host preferences and molecular diversity within the genus Pentalonia (Hemiptera: Aphididae), pp. 383-391 in Zootaxa 4701 (4) on page 387, DOI: 10.11646/zootaxa.4701.4.4, http://zenodo.org/record/399868