The cactus pear (Opuntia ficus-indica) is a crucial plant in Tigray, northern Ethiopia, widely distributed in arid and semi-arid environments. It serves as a seasonal food, and is used in livestock feed, fencing, soil conservation, and environmental protection. Recently, the cactus pear populations in Tigray have been severely affected by an exotic insect, the cochineal (Dactylopius coccus). It damaged cactus pear populations in the region's southern, southeastern, and eastern zones. The Tigray war that broke out in November 2020 exacerbated D. coccus infestation. A study was conducted in the eastern zone of Tigray to assess the impact of the armed conflict on the trends of this infestation and propose sustainable management approaches for sustainable cactus pear production in post-war Tigray. Both primary and secondary data were collected and analyzed. The findings revealed that D. coccus infestation significantly increased during the war and in the post-war period, compared to in the pre-war period. The number of districts involved and level of D. coccus infestation of cactus pear populations increased. The rapid spread was attributed to the interruption of pest management activities due to the armed conflict. To mitigate the spread and ensure sustainable cactus pear production, this study recommends different management approaches to manage D. coccus dissemination and sustainably produce cactus pear in the region, including pest prevention, suppression, or eradication.

In Tigray, northern Ethiopia, prickly pear (Opuntia ficus-indica) is an important crop that serves as a source of seasonal food and income, soil and water conservation, live fencing, and an all-year-round livestock feed. With the intention of increasing the benefits from the crop, an exotic insect, the cochineal (Dactylopius coccus), was intentionally introduced. Nevertheless, the insect has gone wild and caused severe damage to the crop. It has now become a serious threat to the survival of the plant species in the Tigray region. Thus, cactus pear populations and exotic materials were evaluated in the laboratory for their resistance to the insect. The cultivars were tested in 2018 using a complete randomized experimental design with five replications and several plants from three different species of cactus pear: (Opuntia ficus-indica, Opuntia stricta, and Opuntia robusta). Each cladode of the test entries was artificially inoculated with 30 crawlers (mobile first instar) of Dactylopius coccus, less than 24 hours from hatching. Days to first and second molting, days to maturity and number of surviving crawlers on each infested cladode after 7, 14, 21 and 45 days were recorded. The number of crawlers in susceptible species, the weight, size and the relationship between weight and size of insects to the number of crawlers produced were also recorded. There was a highly significant difference among cactus pear species in their resistance to the insect, expressed in terms of the number of surviving crawlers and days to maturity. None of the cochineal crawlers on O. stricta and O. robusta test cultivars were able to reach maturity. On the other hand, most of the cochineal crawlers inoculated on the O. ficusindica lines were able to reach maturity and produce new offspring. The average period for first instar, second instar, maturity and life cycle of the female cochineal, was 19.4, 15.2, 40.4 and 75 days respectively. Thus, both O. robusta and O. stricta were resistant while all O. ficus-indica lines tested were completely susceptible. Besides, the number of crawlers produced per mature female cochineal was found to have a significant correlation coefficient with the size and weight of individual female cochineal. In areas where O. ficus-indica is challenged by D. coccus, suitable cultivars of O. stricta and O. robusta could perhaps perform the same services that were previously filled by O. ficus-indica.